Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: GeForce GTX 660 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.71
Broken: version: 2.93.0 Alpha, branch: master, commit date: 2021-01-23 21:10, hash: rBded9484925ed
Short description of error
Same issue as we had here T71759: Sculpt/Vertex/Weight Paint Brush Size Gets Undone After Undoing a Stroke and same reason to fix it or exclude from undo.
Stroke undo symmetry too.
Please test if undo grabs something else.