This is not new for 6.3.1 and it is not unique for HAP files. The behaviour is the same for all video cues.
It is a known bug/behaviour but not yet scheduled to be fixed.
Hopefully we can get the time to fix it soon.
I just tried it out and had no problems with copy/paste. Did not try all of the tweens but Hue & Saturation and Contrast & Brightness worked fine for me.
Are you still experiencing this issue?