Most terminal emulators have weak spots here and there. I am a long term user of console applications, and right at the end of the 3.x series, Konsole was becoming one of the best. Now I’m running the stock Konsole from 11.2 and it has serious issues with clearing corruption.
I was viewing a site with Lynx (specifically lynx-color) and something caused it to start displaying ghost text. I normally see that only with Elinks and UTF-8 characters, but this was good ole Lynx doing it. I ran the Lynx reset, and it got worse. I ran the reset from the Konsole menu, and it really went bonkers, blanking the whole thing and not repainting at all. I had to kill it, because it affected all three open tabs.