I have noticed same issue on client. Normally after I have traded with someone. As a healer, I normally take payment first and then heal. I notice that sometimes right click functions does not work on newest portion of the chat window. I can often scroll up to older chat and functionality still works. An F5 (refresh) does resolve issue, but not always ideal to do that. Hope this extra info helps you recreate.
I confirm. In trade screen, the chat functions do not work. After confirming, chat functions will work again.
Also sometimes during self-initiated trade, when clicking the prv arrow in:
>> 17:05 xxxxx[8] has accepted your offer to trade.
The whole chat screen scrolls to the top.