Caching issue with annotations in feedback player

[fosterfarrell9]

In production, I experienced the following issue with annotations: A student had made an annotation in a video, and that annotation was shared with me. I noticed the anotation when I opened the feedback player. Then I went through the other videos of my lecture and was puzzled to see the exact same annotation in all of them, always at the same time (when it did not make any contextual sense). It turned out that the annotation vanished in the feedback player when I did a page "shift reload". After that I opened the feedback player for the video that actually contained the annotation and noticed that it had been gone. A "shift reload" of the page made it reappear. Apparently, there are some caching issues here. I can reproduce the behaviour in development.