Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce RTX 3090/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.89
Broken: version: 2.92.0, branch: master, commit date: 2021-02-24 16:25, hash: rB02948a2cab44
Worked: (newest version of Blender that worked as expected)
Short description of error
When moving something with proportional editing on (and connected only selected) Together with X-mirror turned on. A seperate mesh's verts will be moved back. Despite not being connected
Exact steps for others to reproduce the error
Open attached blend file
make sure proportional editing is on,
make sure x-mirroring is on,
select a vert somewhere around the mouth.
notice how some verts on the teeth now move back all on their own, despite not being connected or touched.
Turning either proportional editing, or x-mirror off fixes the issue, but it shouldn't be happening even if they're on.