In short, what happens to me is that when I try to interact with the Mouse on certain buttons it does not recognize the input, it does not even change to the stilebox with the Mouse on it. It doesn't seem to follow any specific pattern, but when it happens in a scene it always happens. It has happened to me in both 4.1 and 4.2. PS: It happens with both Vulcan and OpenGL
I'm not sure what your problem is, I tested several buttons and they didn't have issues. If you send a photo or video of your game and code, I might be able to see what went wrong.
Other than that, all I can tell you is to make sure all of your buttons are identical, just to narrow down the inconsistencies.