How to reproduce
Seed: -6549889454106593879
Coordinates: /tp @s -4943.64 87.00 -5991.67 162.45 33.30
Linked issues
is duplicated by
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will it get fixed?
Please provide seed and coordinates.
I was able to find an example of this, as did a friend of mine in a different world. So it doesn't appear to be that rare. Details for the world I found it in are below.
Seed: -6549889454106593879
Coords: -4942/88/-5994
Confirmed in 16w39b
seed= -2616598912048192895
x=97 y=89 Z=-7212
I hope the seed is still working in the B snapshot
Confirmed in 16w39c
Confirmed in 16w40a
Screenshot added for example of 2 instances of this happening in the same mansion.
Confirmed in 16w41a
Confirmed in 16w42a
i see this too
Still in 16w43a
Another example:
XYZ: 22528, 85, -10985
Seed: 5596122738704322835
Large Biomes generator setting.
But, of course, it occurs to me after the fact to mention that this example world was generated with "Large Biomes".
This doesn't appear to be just missing rows for the stairs, I found another missing slice, this time of wall, in the same mansion I referred to in my previous comment.
XYZ: 22568, 80, -11009
Facing North.
Seed: 5596122738704322835
Large Biomes generator setting.
Confirmed in 16w44a
I was wondering whether it would be worth updating the title of this bug report to be a bit more descriptive of the actual issue. Along the lines of "Missing rows of oak planks and carpet at the top of the stairs (going to the 3rd floor) in some Woodland Mansions"?
Confirmed in 1.11-pre1
Confirmed in 1.11
Confirmed in 16w50a
Confirmed in 1.11.2
Confirmed for 1.13.1.
Confirmed for 1.13.2-pre2.
Found this today in 19w11b with seed 5196832748511568602 around 9340 94 -8229

There is a similar thing I saw. It is where some hallways will just spawn not connecting to the entrance. So they are just a closed off hallway with rooms and spawning illagers.
Can confirm in 20w51a.
Can confirm in 21w03a.
Can confirm in 21w05b. This can be seen in almost every mansion.
Can confirm in 21w06a.
Can confirm in 1.18.1.

Can anyone provide examples of a woodland mansion where this does not happen?
Can confirm in 22w06a.
[media]Version: 22w06a
Seed: 3969471135687155145
Coordinates: /execute in minecraft:overworld run tp @s -5955.57 93.94 -3468.40 89.39 48.00

Here's an example of a mansion generated in 1.18.2 pre-release 1 that isn't missing the row of birch planks. However, the carpet still ends abruptly, which doesn't happen anywhere else. Should this be reported separately?
[media]
Can confirm in 1.18.2.
[media]Version: 1.18.2
Seed: 5674588914129534515
Coordinates: /execute in minecraft:overworld run tp @s 2807 87 4510 -329 56

Affects 22w14a:
[media]
can confirm on 1.16.5 (with mods).
[media]Jacob, affected versions only matter for latest release/snapshot, or the first version the issue appeared in (latter being helpful information to find the cause), nor do modded confirmations hold any merit.
okay.
Can confirm in 1.19 and 22w24a.
Version: 1.19
Seed: 4373241205666815302
Coordinates: /execute in minecraft:overworld run tp @s 583.49 85.00 -2032.42 141.22 40.81
Version: 22w24a
Seed: -1218851612612966176
Coordinates: /execute in minecraft:overworld run tp @s 7888.81 129.71 8408.65 222.61 51.27
Can confirm in 1.19.2.
Version: 1.19.2
Seed: -5025199615634886011
Coordinates: /execute in minecraft:overworld run tp @s -716.71 94.51 399.33 -108.94 52.67
In 23w40a

Confirmed in 1.21.3
Duplicate of MC-96998