Polish and Layer brushes do not work with symmetry
Hello @magilla,
They appear to be working fine for me:
Your mesh may not be symmetrical along a global axis. Try enabling L.Sym (Local Symmetry) found on the right side of the default viewport, or in the Transform menu. If symmetry then works as expected it means your mesh is symmetrical across its own center, but is not symmetrical in the worldspace.
You can force symmetry by using Tool> Geometry> Modify Topology> Mirror and Weld. If your mesh has subdivision levels, you will have to freeze them first.
Good luck! 