I believe I am having the same issue. It freezes adding, deleting + moving points on a single glyph until I restart Robofont (I can edit the other glyphs, however, it doesn’t freeze the whole program).

Sometimes the deleted points are indeed deleted, moved, etc. after restarting, but sometimes not, I haven’t figured out what makes the difference. This seems to happen when copying + pasting several components into the glyph, but I am not sure if this is connected.