Corrupted clip picking up video from other clips - solved

I was having a bizarre problem where one of my clips on an upper layer (that I was keyframing the opacity and motion as an overlay) started picking up data/video images from the clip below and also from other clips not in that section of the timeline. I tried deleting and reloading the clip, renaming, and all kinds of other things too numerous to list or to remember.

The solution: reboot computer. I tried opening and closing the program but that did not solve the problem. Posting in case someone else has this problem.