System Information
Operating system: Windows
Graphics card: GeForce

Blender Version
Broken: 3.1.2
Worked: Not sure

Short description of error
-Draw anything in grease pencil
-Add subdivide modifier
-Go to sculpt mode
-Use Push brush to move the last vertex of any stroke.

You'll notice that while smooth modifier is active, you can't move the last vertex of every stroke. You have to disable it to work normally.

Note that Push is one of the brushes that fails. But, almost all brushes will fail the same way.