I know it was talked about several times, but somehow never got into feedback properly, so: on mobile IE, chat 'blocks' on a certain snapshot, and whenever a new message comes - it resets to that state, for unknown reasons. Basically, you have log of messages, new one comes through - you see the same backlog, If you refresh, you can see all of them, but since browser tries to connect, you can see it for a few seconds at most, because after connection - it is back to said 'snapshot'.
Basically limits ability to browse site meaningfully from a phone with Windows entirely.