Confirmed but it's not the copying action that does it but the overlapping of the new item onto the original. Take any item and slide it into an altered curve, and back out, it will ruin it if crossfading occurs.
Made a post about this issue (check here: https://forum.cockos.com/showthread.php?t=223505 ), just to find out that actually many people have already reported this bug. I hope this gets addressed soon!