Hey @ben, I have been seeing a few of these appear in a module window when submitting posts recently, the last happened just a few moments ago when I was updating the Facebook Blocked Users list post. I wondered if it could be because of the odd characters in some of the names of these users, however, on the second submit it always seems to work so I’m guessing that isn’t the case. Not 100% sure what platform this is all running from but I wondered if there were any server logs or perhaps logs within Discourse that would show anything of interest. I have noticed it a few times recently, not always with that post, and at varying times of the day/night.
I think this is solved.