Symmetry does not work correctly

Experimenter

I have two sperate cubes and welded them together than I activate symmetry in the Properties tab. It works well. But at a few areas the symmetry does not work. I select a point, an edge or a face at the left cube and at the right cube does not select. When I select something in an other area of the cube it works well. What do I wrong?

Roygee

Symmetry modelling in Hexagon has never worked well enough to put faith in it.  If you need a symmetrical model, best to model one half, then apply symmetry and weld.