System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: AMD Radeon RX 5700 XT ATI Technologies Inc. 4.5.14757 Core Profile Context 20.12.1 27.20.14501.28009
Blender Version
Broken: version: 2.92.0 Alpha, branch: master, commit date: 2021-01-08 23:19, hash: rB9c074548165a
worked: it has been in blender for a long time, I already reported it but I wasn't able to reproduce it consistenly at the time
Exact steps for others to reproduce the error
if you have an object that has an armature modifier and sculpt on it, once you leave sculpt mode the armature pose gets "baked" into the multiresolution.
also it seems that it may only happen after you ctrl-z (maybe thats why I couldn't reproduce it before as it was a missing step)