Hi
I cannot confirm those glitches on macOS. Especially the second one seems very strange to me. At this point I think it would be best if you add a bug report. If you are running the most recent macOS (Mojave), you could also create a video very easily (cmd+shift+5 for the builtin screen recorder) and attach that to the bug.
Please CC me on the bug, as I am currently messing around with the context menus, and it might be caused by that. But I would more prominently suggest, that the used Qt version is buggy. Nethertheless, we have to investigate.
cheers
Roland