I don't know if it's the proper channel but I did start a Github issue here with technical notes - https://github.com/vimeo/player.js/issues/1119.  They are wanting more information about how the Vimeo player is rendered, ideally with a small sample page that demonstrates the issue, but I'm not sure what that would look like.

I should also mention I have tried a handful of different videos and they all exhibit the same behavior, so it's not specific to this session.