I was struggling with this issue as well. I made an entirely new master sequence, and when going to render it out, I was seeing other camera shots instead. Matter of fact, the program would taunt me by letting these little gremlin assets pop up temporarily in my world outliner while the video was rendering, and disappear promptly afterward lol.
Tried searching them up to delete them; nothing. Even went into the project files on my pc. Turns out I hadn’t gotten rid of a few Matinee tools. Hope my blonde moment might help someone else running on 2 hrs of sleep! XD