Sometimes the text ui, it stops updating. It still receives the messages (they don't stop at the approver) but they are not shown. It is not very easy to reproduce, I think it might be caused by a race condition happening if a message is sent in the exact same time you receive one.
Do you know if you were playing with the chat-plasmoid around the time you saw this? Could be a symptom of https://bugs.kde.org/show_bug.cgi?id=303532
No, I didn't have any chat-plasmoid on my desktop. It happened to me at least 4 times, all of them while both me and my contact were sending very quick messages, that's why I thought about the race condition
Have you seen this with Renkoo? I suspect your theme could just be at fault. (as I know you use a different one) If it happens, open the web inspector, and look for errors.
Actually I didn't have this problem recently. I'll try with the Renkoo theme for a while, and reopen this if it happens again
As there was no update for 6 months, I'm closing as per comment #4.