I've had multiple occasions where a chat simply disappears. According to Grindr's support both this can be because of several things, they blocked me, they deleted their profile or they were banned.

I think there should be an option to see why they are suddenly disappearing mid conversation. It sucks when you're having a decent conversation and suddenly you're busy responding to a question and the chat disappears.

Personally I think this is a bug but if not I think we should know if the guy was banned, like hey the guy who just disappeared was banned because he threatened someone. Or "Sorry he's not interested, you can't contact him anymore"