I think I found the bug that was causing videos to get shown over and over again. What would happen would be if two people were watching the same video at the same time, one could submit their observations and cause the other ones to validate, and have it marked as canonical -- this would set a field in the database for that video segment to be VALIDATED which means it shouldn't be shown to anyone else. Then if the other person submitted their observation, it could potentially overwrite the VALIDATED field to just WATCHED, meaning it could be shown to people again. If this happened it would never flip back to validated. This should be fixed now.

More...