Oh … I think I’ve found part of the problem … on multiple sites (even on Meta) I can reproduce this:
When I paste a link into Title it doesn’t always convert into a Title … sometimes you are left with a URL. This is an intermittent issue … is this rate limited locally or remotely, somehow? Interestingly, once it works, you can delete it and it will work again instantly … as if being cached?
Rebuilding the HTML of the first post does not fix the Title even if it’s still a URL.
NB I don’t see any javascript errors on console when this fails.