System Information
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

Blender Version
Broken: version: 2.92.0 Alpha, branch: master, commit date: 2021-01-02 22:51, hash: rBc7e92e379d62
Last worked i have: blender-2.92.0-4797c13e8f3a-windows64
First broken i have: blender-2.92.0-8491e4ab8636-windows64

Short description of error
To reproduce: add object, enter sculpt mode, remesh with hotkey, touch with mask brush.
If you exit to object mode and back to sculpt, mask will work fine again.