The process to reproduce this is the same as MCPE-23416, MCPE-97295, and MCPE-141499. To get a missing chest specifically use these steps:

1. Set render distance to 8 and turn on the auto-save icon.
2. Create a world using the "Stronghold Below" seed with simulation distance 4 or 6.
3. /tp 1126 70 -15
4. Move to 32 < Z < 47, then quickly back to Z < 0, and wait.
5. Once the auto-save icon appears, /tp 1126 27 201.

Expected result

Chests at Z = 202 and Z = 209.

Observed result

One or both chests are missing.
Missing chest.mp4

This is hard to reproduce because it will happen at random times.

Steps to reproduce

1. 1 enter a stronghold
2. 2 search for corridor chests ( if none of them is missing, then try the same seed a few time.)

Observed result:
Sometimes a corridor chest is missing, resulting in an empty chest holder and missing loot.

Expected result
All chest should generate
Seed:
-27149278 (Stronghold Below)
Coords:
1126 27 201