Thanks for tagging us. When you mention about to YouTuber's videos not showing up, are you referring to your Homepage or Search results? Let us know.
Thanks for the details. Have you tried sorting the videos by clicking the 'SORT BY' option on the right-top corner of the videos tab? It has options for you to sort videos in the most popular/date added(oldest/newest) format, so you can watch your desired videos. Hope this helps.