I’ve been updating a few things in the background and the same happened to me. Just refresh the page and it should come back.
FYI We’ve got a strange bug that I’m trying to track down so I can report it to Discourse.
Only on PC (I think), if you are reading a post that is a reply, and you click on the link to the post that it is replying to and it expands to show the replied to post…
Then something breaks and you can’t like things anymore (or at least the like heart stops) and new posts in the thread are no longer automatically updated.
It’s not Discourse’s bug, it’s one of the plugins we use on top of Discourse. I’ve just got to narrow it down so expect some more annoying fannying and upgrading over the next day or so.