In the past, I'vere-rendered as I changed underlying graphics when dealing with green screen. This time, I tried exporting clips in ProRes 4444 with an alpha channel and bringing the clip back in so that I didn't have to keep re-rendering as I changed tracks underneath.
The problem is, graphics in lower tracks are randomly appearing or not appearing. For example, I have a png that appears on a lower track...many clips of the same thing - just repeating. Below that, I have a looping background movie. As one clip ends and the SAME clip restarts again, it randomly will or will not be visible for the length of the clip (it doesn't go invisible in the middle of the clip unless a higher or lower clip stops or starts). If I EXPORT the project, all clips play exactly as they should in the exported movie. The problem is ONLY when playing within FCP. Of course, this puts a severe cramp in editing.
I didn't find a thread specifically about this, but I'm sure I've just bumped into something common (at least I hope that's the case).