Sorry did not think to screen grab it but the user was eePez or something like that. As soon as I saw what happened got the hell out because didn't want to screw up another persons account. Also had a small blue and orange picture beside his or her name
Something similar happened to me a few times recently, as I had just migrated instances and was swapping back and forth between accounts relatively often. I think it was that same username you just mentioned, because that sounds familiar. Only I do not think I was actually logged in as them. Just refreshing showed my actual account like normal. This was all on Thunder/Android.
Currently on Firefox laptop when it happened. First time ever it happened just want to make sure people with mean intentions don't get the same glitch and then do something bad with the accout.