Operating system: Linux-5.10.9-051009-generic-x86_64-with-debian-bullseye-sid 64 Bits
Graphics card: Radeon RX 570 Series (POLARIS10, DRM 3.40.0, 5.10.9-051009-generic, LLVM 11.0.0) X.Org 4.6 (Core Profile) Mesa 20.2.6
Broken: version: 2.92.0, branch: master, commit date: 2021-02-24 16:25, hash: rB02948a2cab44
Worked: 2.91.2 works perfectly well
Short description of error
Opening a file with dyntopo enabled and clicking undo disables dynopo and corrupts the mesh. The same happens when creating a new file, clicking dyntopo, making any change to the mesh and clicking undo again.
Exact steps for others to reproduce the error
- File -> New -> Sculpting
- Enable dyntopo by clicking on the button on the toolbar to the right of mirror options (XYZ buttons).
- Draw one single line on the sphere
- Click Ctrl+z two times.
- Draw on the sphere again.
As a result, the dyntopo is disabled and parts of the mesh are broken (sometimes it creates holes, sometimes face sets), which can easily be tested by trying to draw on it again.
Clicking Ctrl+z again after drawing on the broken mesh seems to fix everything (at least in the simplest example with the default sphere).
I also tested it on my laptop on Windows where I did a fresh installation of Blender 2.92 build from the official website without any changes to any default settings and the result is the same.
It may look as a silly bug, but I believe that it affects me also long after this simple example, because I got my more complex mesh corrupted and dyntopo disabled after clicking Undo several times. The corruption is different: sometimes a subset of faces disappears, sometimes some new face sets appear.
I apologize if it is a known bug, I did my best searching on the bug tracker and didn't find anything relevant by the keyword "dyntopo".