No Thumbnail for Unlisted Vimeo Videos

This seems fine for me (I tried posting on try.discourse.org):

https://vimeo.com/928819246/c8f7325d2a

Upon clicking Play:

Since you’ve been changing video privacy settings it’s possible that the problem is related to the onebox cache; since you’re on a hosted plan please email us with details of the specific site and post that’s not working, or message @team here on meta for official support and we’ll help you out.