Thanks. I may try the 00:00, and see if that works.
Still no luck.....not sure what happened. Seems like if the timestamps show up and work in the description, then the chapters would show up on video.
How many chapters did you try to use? I doubt you tried to use more than 50, but they actually won't work at all if you have more than 50. I had an hour long video that I wanted to segment into differant sections and I initially had more than 50 and none of them would show up. I reduced it down to about 30 chapters and it worked fine.
Also, each chapter MUST be 10 seconds long minimum I believe, so if you have a chapter that's less than 10 seconds, that will theoretically mess up ALL your chapters. I haven't tested to see if for example, chapter 20 is 9 seconds and everything before that chapter works, and everything after that chapter doesn't work, but you say that your first chapter is 00:00 (which is correct) I have a gut feeling that your second chapter being at 00:10 might be causing the issue. I don't like having chapters at 10 seconds even if YouTube says you can, I always make sure my chapters are minimum of 11 seconds.
So make sure each chapter length is longer than 10-11 seconds, and you don't have more than 50
You also must have at least 3 chapters. I'd go with 4 minimum just to be safe.
Video Chapters break up a video into sections, each with an individual preview. Video chapters add info and context to each portion of the video and let you easily rewatch different parts of the video
support.google.com
So if you have MORE than 3 chapters (it can be exactly 3, I just did a test) LESS than 50. each chapter is longer than 10 seconds and you're STILL finding issues, then it might be a bug.
Oh and make sure you haven't made any timestamps before 00:00 that will mess with it (I had one where I said at the start "video starts at 01:50 (just an example) and that disabled the timestamps and chapters I had after. When I removed the timestamp before that, the chapters worked after 00:00
