I just updated to 2.9 and am experiencing some strange behavior with the Mirror command and mesh UVs. Is this a bug or some weird setting I don't know is enabled?
Here is my setup:
If I go into edit mode on the cube, Shift-D duplicate the mesh, mirror it across the X axis with the 3D cursor as the pivot, it at first seems OK but after exiting and entering edit mode again, the UVs of the mirrored portion of the mesh are messed up.
Any clue what's going on here?