Bedrock Edition repost of MC-270696.
"wall_dispenser" dispenser traps can generate behind walls in trial chambers, rendering them pointless.
Seed: -3451608330957216249
Coordinates 1: 91 -22 228
Coordinates 2: 623 7 205
1.21.30.21 ~ 1.21.30.23
Seed: -8147499510490594898
Coordinates: 867 -37 116
Steps to Reproduce:
Create a new world using the given seed.
Enter Spectator mode.
Teleport to one of the given coordinates.
Observed Results:
"wall_dispenser" dispenser traps can generate behind walls.
Expected Results:
"wall_dispenser" dispenser traps would not generate behind walls.
Linked issues
Attachments
Comments 4

This appears to only happen with "wall_dispenser", although I don't know if "chamber" and "floor_dispenser" can generate in the first place.
"floor_dispenser" can generate in the "assembly" room.