Anyone else with this problem?

My chat window stops scrolling randomly. Sometimes it happens after I've scrolled back up to read something I missed, but often happens for no reason. I've tried the usual procedure of typing some text in, and sometimes this sorts the problem for a few minutes, but often it doesn't. And there's no indication that it's happened unless you manually scroll down and find a whole lot of text has been written and you hadn't seen it!

This is so irritating when in a party, and relying on Party chat for alerts/instructions in an encounter.