When a hopper sends a kind of items in a chest and the player adds the same kind of items at the exact same time as the hopper, the items initially in the chest are deleted.
Note
The bug was experienced on a realm in survival but works in solo and every game modes.
The bug is a bit hard to reproduce you have to get the timing or brute force it. (Took me 5mins when I recorded it, by brute forcing it)
How to Reproduce
In creative mode, take a hopper and 2 chests. One chest input one kind of items in the second one.
Lock the hopper to prevent items from being transferred for the moment.
Choose an item and fill entirely the top chest (you could try several times and compare the number of items before and after the manipulation).
Take the same item in your hands, do little packs of it to have multiple attempts.(the number of items your adding to the one the slot being filled in the chest is superior to 64 the bug seems to not occurs as the stack and the extra items just switches places).
It's a matter of timing (or luck), try to reproduce the rhythm of the hopper in your head or out loud. When you think you have it add the items in hand over the ones in chest. Try again until you succeed.
Finally, lock the hopper again and take all the items to the top chest to confirm the loss (if you haven’t seen the bug occurred.
Here is a [link|https://clipchamp.com/watch/Lfi9rpnaZ3z] to a video of me reproducing the bug. I succeed the bug at 0:44.
(ClipChamp is a Microsoft Application)
Expected result
Initial:
X: items in the chest
Y: items in your hand
Final:
X+Y+1 in the chest
(+1 is the item send by the hopper)
Observed result
Final:
Y+1 in the chest
X disappeared
As I experienced in solo after your answer. I managed to reproduce the bug several times. And so I tested with 8 items in hand and got 9. Which led me to believe that it was the items in the chest that were disappearing (X). But when experienced the first time by accident I lost 47 scraps so may I lost X+Y? I don’t know. Moreover, to complete my report I decided to add a video and as I tried to reproduce the bug I’ve done it with X+Y > 64, that I thought impossible before. And it resulted to be another result:
40 + 32 + 1 => 24 + 8 (in hand)
And: 24 + 8 = 32
Here the result is Y:
When items are added to another items if the amount is greater than 64, You’ll get the rest in your hand. Here 40 + 32 is 64 + 8. So X disappeared as expected and the items even divided correctly. I think the item send by the hopper disappear too in that case because it’s than greater than 64. Maybe that's what happened when I was playing and experienced the bug.
Linked issues
is duplicated by 8
MCPE-162008
Items deleted when shift clicking into an inventory that is being changed by a hopper
Resolved
MCPE-174789
Items get erased if they come from 2 sources into 1 container simultaneously
Resolved
MCPE-175542
Missing items from Hopper Minecart
Resolved
MCPE-178852
Items vanishing when moving into containers whilst a hopper is as well.
Resolved
MCPE-179006
If you insert an item into a crafter block at a certain time, the item will disappear.
Resolved
Attachments
Comments 6
I can see that at 0:46 in the video you place a stack of 32 onto a stack that is going from 40 to 41,. The stack in the chest goes to 24 and the stack being held goes to 8. The 41 in the chest slot is lost/deleted. That is why the final chest has a stack of 23 in its last slot ( 64 - 41 = 23 ).
I was able to reproduce this in a local world exactly as described an shown in the video. I also checked whether it only happens when the hopper and chest are in separate chunks, and that hunch proved false. It happens anywhere.
Since MCPE-174789 was resolved as a duplicate of this bug even though it seemed a bit more broad than this one, I'll add something here: today, a little over three stacks of items in my supersmelter were deleted, which I strongly suspect happened in interactions between hoppers and moving furnaces (in a piston feed tape in the supersmelter), either when hoppers added sand to the furnaces or when other hoppers removed glass from them. This happened even though I didn't directly interact with the problematic hoppers by hand, so it looks like whatever's causing this bug (or something similar) is capable of deleting items when hoppers do stuff at unlucky timing, and not just when the player is involved. I'm running 1.20.15 on iOS 16. I never noticed items being deleted in 1.19 (in particular, I know I managed to smelt 5 shulker boxes at once in 1.19 without anything being deleted), so this might be a new issue.
A different issue from the one in my previous comment: can confirm that this bug affects 1.20.15, since I experienced the exact phenomenon described here yesterday (putting items into a chest while a hopper was putting more of that item into the chest, resulting in roughly a stack of items being deleted). This issue can definitely occur in ordinary gameplay for people with automatic farms.
Easier reproduction steps in case it helps.
To set it up:
Place a Hopper Minecart with a chest above it
Place a stack of items in the chest
Now place another stack of the same item directly into the Hopper Minecart while the other items are being pulled in from above
Expected result:
When all items are finished moving into the Hopper Minecart, I would expect two stacks of items (given the example above).
Actual result:
Less than two stacks of items will remain in the Hopper Minecart. In some cases, half a stack will be missing.
Does this only occur on a realm or does the same issue occur on a local copy of the world?
Please edit the Description to include a list of steps to reproduce the issue, as shown here:
(add screenshots or video to help explain the issue)
This report has been temporarily closed as Awaiting Response. It will automatically reopen when you add information. Please follow the format shown and include all sections (steps, observed, expected). Reports that do not contain all of the requested information and complete steps to reproduce the issue may be closed as Incomplete. For more information please read the Bug Tracker Guidelines.
You may find this Report Creation Form helpful for any future reports you create.