We'd like to help. In total, how many videos are missing? Could you confirm if you can see the videos in the Video Manager page? Also, could you try signing out and signing back in to see if that makes a difference? Let us know.
Appreciate the info. Please send a feedback report directly from YouTube with these steps: https://goo.gl/WdI0BK . While every individual report may not get a direct response, we do review everything and use the details to investigate and fix issues. Thanks.