Various Ominous Banner stacking issues

Do the banners have different names?

They do not, same NBT and everything as well.

Where did you get the banners from?

All are from patrol captains

Confirmed. The only difference is that the 1.14 banner has a redundant id:"minecraft:banner" inside of BlockEntityTag.

I'm experiencing this too bewteen 1.14.2pr3 & 4 ominous banners and 1.14.2 ominous banners

Had this bug, but for some reason manually placing banners and destroying them made them stack again.

After examining the NBT in hexadecimal, I also confirm the redundant id:"minecraft:banner" inside of BlockEntityTag.

This is a bug with all banners, not just the Ominous Banner.

This difference occurs when a banner is placed. A freshly-crafted banner has this redundant tag, whereas a banner that is placed, broken and picked up will be missing this tag.

Here is an example of an identical banner extracted from a player's inventory.

Fresh banner
The redundant "id" tag is on the fifth line.

01 00 04 53 6C 6F 74 06 08 00 02 69 64 00 14 6D  . . . S l o t . . . . i d . . m 
69 6E 65 63 72 61 66 74 3A 72 65 64 5F 62 61 6E  i n e c r a f t : r e d _ b a n 
6E 65 72 01 00 05 43 6F 75 6E 74 04 0A 00 03 74  n e r . . . C o u n t . . . . t 
61 67 0A 00 0E 42 6C 6F 63 6B 45 6E 74 69 74 79  a g . . . B l o c k E n t i t y 
54 61 67 08 00 02 69 64 00 10 6D 69 6E 65 63 72  T a g . . . i d . . m i n e c r 
61 66 74 3A 62 61 6E 6E 65 72 09 00 08 50 61 74  a f t : b a n n e r . . . P a t 
74 65 72 6E 73 0A 00 00 00 05 08 00 07 50 61 74  t e r n s . . . . . . . . P a t 
74 65 72 6E 00 02 74 73 03 00 05 43 6F 6C 6F 72  t e r n . . t s . . . C o l o r 
00 00 00 00 00 08 00 07 50 61 74 74 65 72 6E 00  . . . . . . . . P a t t e r n . 
02 72 64 03 00 05 43 6F 6C 6F 72 00 00 00 0E 00  . r d . . . C o l o r . . . . . 
08 00 07 50 61 74 74 65 72 6E 00 03 64 6C 73 03  . . . P a t t e r n . . d l s . 
00 05 43 6F 6C 6F 72 00 00 00 00 00 08 00 07 50  . . C o l o r . . . . . . . . P 
61 74 74 65 72 6E 00 02 62 6C 03 00 05 43 6F 6C  a t t e r n . . b l . . . C o l 
6F 72 00 00 00 00 00 08 00 07 50 61 74 74 65 72  o r . . . . . . . . P a t t e r 
6E 00 02 62 6F 03 00 05 43 6F 6C 6F 72 00 00 00  n . . b o . . . C o l o r . . . 
0E 00 00 00 00                      . . . . .

Banner that has been placed and broken
Has no "id" tag.

01 00 04 53 6C 6F 74 03 08 00 02 69 64 00 14 6D   . . . S l o t . . . . i d . . m 
69 6E 65 63 72 61 66 74 3A 72 65 64 5F 62 61 6E   i n e c r a f t : r e d _ b a n 
6E 65 72 01 00 05 43 6F 75 6E 74 03 0A 00 03 74   n e r . . . C o u n t . . . . t 
61 67 0A 00 0E 42 6C 6F 63 6B 45 6E 74 69 74 79   a g . . . B l o c k E n t i t y 
54 61 67 09 00 08 50 61 74 74 65 72 6E 73 0A 00   T a g . . . P a t t e r n s . . 
00 00 05 08 00 07 50 61 74 74 65 72 6E 00 02 74   . . . . . . P a t t e r n . . t 
73 03 00 05 43 6F 6C 6F 72 00 00 00 00 00 08 00   s . . . C o l o r . . . . . . . 
07 50 61 74 74 65 72 6E 00 02 72 64 03 00 05 43   . P a t t e r n . . r d . . . C 
6F 6C 6F 72 00 00 00 0E 00 08 00 07 50 61 74 74   o l o r . . . . . . . . P a t t 
65 72 6E 00 03 64 6C 73 03 00 05 43 6F 6C 6F 72   e r n . . d l s . . . C o l o r 
00 00 00 00 00 08 00 07 50 61 74 74 65 72 6E 00   . . . . . . . . P a t t e r n . 
02 62 6C 03 00 05 43 6F 6C 6F 72 00 00 00 00 00   . b l . . . C o l o r . . . . . 
08 00 07 50 61 74 74 65 72 6E 00 02 62 6F 03 00   . . . P a t t e r n . . b o . . 
05 43 6F 6C 6F 72 00 00 00 0E 00 00 00 00         . C o l o r . . . . . . . .

Hex dumps for Ominous Banners from a player's inventory.

Ominous Banner with redundant id tag

01 00 04 53 6C 6F 74 04 08 00 02 69 64 00 16 6D   . . . S l o t . . . . i d . . m 
69 6E 65 63 72 61 66 74 3A 77 68 69 74 65 5F 62   i n e c r a f t : w h i t e _ b 
61 6E 6E 65 72 01 00 05 43 6F 75 6E 74 10 0A 00   a n n e r . . . C o u n t . . . 
03 74 61 67 0A 00 0E 42 6C 6F 63 6B 45 6E 74 69   . t a g . . . B l o c k E n t i 
74 79 54 61 67 08 00 02 69 64 00 10 6D 69 6E 65   t y T a g . . . i d . . m i n e 
63 72 61 66 74 3A 62 61 6E 6E 65 72 09 00 08 50   c r a f t : b a n n e r . . . P 
61 74 74 65 72 6E 73 0A 00 00 00 08 08 00 07 50   a t t e r n s . . . . . . . . P 
61 74 74 65 72 6E 00 02 6D 72 03 00 05 43 6F 6C   a t t e r n . . m r . . . C o l 
6F 72 00 00 00 09 00 08 00 07 50 61 74 74 65 72   o r . . . . . . . . P a t t e r 
6E 00 02 62 73 03 00 05 43 6F 6C 6F 72 00 00 00   n . . b s . . . C o l o r . . . 
08 00 08 00 07 50 61 74 74 65 72 6E 00 02 63 73   . . . . . P a t t e r n . . c s 
03 00 05 43 6F 6C 6F 72 00 00 00 07 00 08 00 07   . . . C o l o r . . . . . . . . 
50 61 74 74 65 72 6E 00 02 62 6F 03 00 05 43 6F   P a t t e r n . . b o . . . C o 
6C 6F 72 00 00 00 08 00 08 00 07 50 61 74 74 65   l o r . . . . . . . . P a t t e 
72 6E 00 02 6D 73 03 00 05 43 6F 6C 6F 72 00 00   r n . . m s . . . C o l o r . . 
00 0F 00 08 00 07 50 61 74 74 65 72 6E 00 02 68   . . . . . . P a t t e r n . . h 
68 03 00 05 43 6F 6C 6F 72 00 00 00 08 00 08 00   h . . . C o l o r . . . . . . . 
07 50 61 74 74 65 72 6E 00 02 6D 63 03 00 05 43   . P a t t e r n . . m c . . . C 
6F 6C 6F 72 00 00 00 08 00 08 00 07 50 61 74 74   o l o r . . . . . . . . P a t t 
65 72 6E 00 02 62 6F 03 00 05 43 6F 6C 6F 72 00   e r n . . b o . . . C o l o r . 
00 00 0F 00 00 0A 00 07 64 69 73 70 6C 61 79 08   . . . . . . . . d i s p l a y . 
00 04 4E 61 6D 65 00 3D 7B 22 63 6F 6C 6F 72 22   . . N a m e . = { " c o l o r " 
3A 22 67 6F 6C 64 22 2C 22 74 72 61 6E 73 6C 61   : " g o l d " , " t r a n s l a 
74 65 22 3A 22 62 6C 6F 63 6B 2E 6D 69 6E 65 63   t e " : " b l o c k . m i n e c 
72 61 66 74 2E 6F 6D 69 6E 6F 75 73 5F 62 61 6E   r a f t . o m i n o u s _ b a n 
6E 65 72 22 7D 00 00 00                           n e r " } . . .

Ominous Banner without redundant tag

01 00 04 53 6C 6F 74 01 08 00 02 69 64 00 16 6D   . . . S l o t . . . . i d . . m 
69 6E 65 63 72 61 66 74 3A 77 68 69 74 65 5F 62   i n e c r a f t : w h i t e _ b 
61 6E 6E 65 72 01 00 05 43 6F 75 6E 74 10 0A 00   a n n e r . . . C o u n t . . . 
03 74 61 67 0A 00 0E 42 6C 6F 63 6B 45 6E 74 69   . t a g . . . B l o c k E n t i 
74 79 54 61 67 09 00 08 50 61 74 74 65 72 6E 73   t y T a g . . . P a t t e r n s 
0A 00 00 00 08 08 00 07 50 61 74 74 65 72 6E 00   . . . . . . . . P a t t e r n . 
02 6D 72 03 00 05 43 6F 6C 6F 72 00 00 00 09 00   . m r . . . C o l o r . . . . . 
08 00 07 50 61 74 74 65 72 6E 00 02 62 73 03 00   . . . P a t t e r n . . b s . . 
05 43 6F 6C 6F 72 00 00 00 08 00 08 00 07 50 61   . C o l o r . . . . . . . . P a 
74 74 65 72 6E 00 02 63 73 03 00 05 43 6F 6C 6F   t t e r n . . c s . . . C o l o 
72 00 00 00 07 00 08 00 07 50 61 74 74 65 72 6E   r . . . . . . . . P a t t e r n 
00 02 62 6F 03 00 05 43 6F 6C 6F 72 00 00 00 08   . . b o . . . C o l o r . . . . 
00 08 00 07 50 61 74 74 65 72 6E 00 02 6D 73 03   . . . . P a t t e r n . . m s . 
00 05 43 6F 6C 6F 72 00 00 00 0F 00 08 00 07 50   . . C o l o r . . . . . . . . P 
61 74 74 65 72 6E 00 02 68 68 03 00 05 43 6F 6C   a t t e r n . . h h . . . C o l 
6F 72 00 00 00 08 00 08 00 07 50 61 74 74 65 72   o r . . . . . . . . P a t t e r 
6E 00 02 6D 63 03 00 05 43 6F 6C 6F 72 00 00 00   n . . m c . . . C o l o r . . . 
08 00 08 00 07 50 61 74 74 65 72 6E 00 02 62 6F   . . . . . P a t t e r n . . b o 
03 00 05 43 6F 6C 6F 72 00 00 00 0F 00 00 0A 00   . . . C o l o r . . . . . . . . 
07 64 69 73 70 6C 61 79 08 00 04 4E 61 6D 65 00   . d i s p l a y . . . N a m e . 
3D 7B 22 63 6F 6C 6F 72 22 3A 22 67 6F 6C 64 22   = { " c o l o r " : " g o l d " 
2C 22 74 72 61 6E 73 6C 61 74 65 22 3A 22 62 6C   , " t r a n s l a t e " : " b l 
6F 63 6B 2E 6D 69 6E 65 63 72 61 66 74 2E 6F 6D   o c k . m i n e c r a f t . o m 
69 6E 6F 75 73 5F 62 61 6E 6E 65 72 22 7D 00 00   i n o u s _ b a n n e r " } . .
00

.

Does this issue still happen in 1.15-pre1? I tried to reproduce with @unknown's description of the issue, but wasn't successful.

I could not reproduce in 1.15 pre-3 using the following steps in a 1.15 test world:
1. Give player some blank banners, dyes and an axe
2. Switch to survival mode
3. Craft one banner with a pattern using a loom
4. Copy banner using crafting table
5. Place one banner
6. Break banner using axe
7. Pick up banner -> the dropped banner stacked correctly with unplaced banner in inventory

However, these steps are incomplete and do not take into account the actual cause of the issue. Banners created before 1.13 had the id:banner tag. When worlds are upgraded from pre-1.13 worlds, this tag is not removed. This causes the bug. For some reason, some of the Ominous banners also have this tag.

The following reproduces the issue in 1.15 pre-3:

1. Create a new creative mode world using version 1.12.2.
2. Give player some blank banners, dye and an axe
3. Switch to survival mode
4. Craft one banner with a pattern using a crafting table
5. Copy banner using crafting table
6. Quit the game
7. Load the game up in 1.13 or any newer version (1.15 pre-3 can be used)
8. Place one banner with the pattern
9. Break banner using axe
10. Pick up banner -> the dropped banner does not stack with unplaced banner in inventory

This does not work if the banner is blank. The banner must have a pattern.

For convenience, I have created a 1.12.2 world with some banners for testing purposes. This world is in "BT1122.zip".

Still an issue in 1.15 pre-4. See my previous comment for instructions on how to reproduce the issue.

Still an issue in 1.15.1. Confirmed using BT1122 world.

Still an issue in 1.15.2

It's not just banners from previous versions. Here's steps to reproduce my end of the banner stacking, @unknown.
1. Kill a captain Illager to get his banner. It can be any type of captain, to my knowledge all of the captain banners will stack together.
2. Collect some of the banners from an outpost.
Despite the fact they're supposed to be the same exact banner, ones that are dropped from captains, and broken blocks are different in that the block drop versions do not stack because they don't have their banner info hidden, whilist captain banners do.

Another thing to note; if you place a captain banner and break it, it will stack with banners from the outposts.
If the original submitter of this is no longer active, I'd like to request ownership of this issue.

This happened to me when I upgraded my world from 20w06a to 20w08a, ominous banners that were generated in the previous version didn't stack with ominous banners from the new version. Both banner stacking issues are still present.

Still an issue in Snapshot 20w13a. banners dropped by captains are different than ones made or taken from outposts.

Thank you for posting. Due to moving process I recently haven't been able to post updates.

I killed 3 patrols it gave me 3 Ominous Banners in total and they could be stacked.

It doesn't show the patterns until you place the banner, but then you can't stack that banner with the other 2 which haven't been placed. If you place these down, you can stack the 3 banners again.

On 1.16 Pre-release 7
Similar issue:
1. Make a custom banners and duplicate to a stack of 16
2. Batch rename in an anvil
3. Place one banner on a block
4. Right click with map (so the custom banner appears on the map)
5. Break the banner
6. The banner will not stack with the rest of the banners similarly named...

Comment: Also banner labels are not uniform in that shorter text appears larger (too large) on maps... I don't know if its intended or not...

Still an issue in 1.16.2

Easy fix: just make minecraft:ominous_banner a distinct block from the others.

In 1.16.4 I killed a captain, took his omnious banner, attempted it to stack with omnious banners I had captured, placed and broken. I noticed, it did not stack and in the chest gui the list of colors differed. The color list of the captured banner listed no colors, while for the broken omnious banners, the listed colors are: Cyan Lozenge, Light Gray Base, Gray Pale, Light Gray Bordure, Black Fess, Light Gray Per Fess. See attached screenshots.
As soon as I placed and broke the captured banner, the color list was changed from empty to the color list of the other broken banners and stackable. So placing and breaking is an in-game workaround.
Update. I just captured another ominous banner, and noticed it does not stack with the other unplaced banner, nor the broken.

Update 2. I just captured 3 ominous banner from consecutive raids, which stack together, but not with the already stored ones: the unplaced and broken ones. I am getting the impression that properties, that I am not aware of, the different captured banners somehow differ.

Also sometimes they just don't stack from the same version for no reason at all. It seems that raid banners and outpost banners are different in some way?

The ones from the outpost were placed in the world before, that's the second case mentioned here.

They indeed are different. Ones on outposts show their banner patterns while ones dropped by captains havw it hidden.

Can confirm in 1.17.1.

Affects 1.19.0 

Banners from Outpost also do not stack with creative inventory ones. 
Placing, breaking and collecting them doesnt appear to cause any issues. 
Not tested with banners from multiple versions, only 1.19.0.

Affects 1.19.10.

Just went through a lot of hassle trying to configure a wandering trader to buy illager banners just to discover that he won't accept those from the creative inventory while testing.

Glad to know now that this is a bug and not something that I am doing wrong.
(attached capture).

See: minecraft bug - illager banners not stackable.png

@unknown This bug tracker is for Java Edition only.

Like [MC-140565], this issue was fixed in 24w09a.