Hi mrmazda,
thank you for replay!
You said it right. On the other side the Discover message says “report this issue” not “report as bug”. Further I think, this issue is not important for me. So I opted to inform people that are more familiar with issues and system bugs.
It was only an attempt. I upgraded to Leap 15.4 and found a KMail (5.19.3) with a bug, which has been already solved in ver. 5.22.1. So I wanted to iInstall this version, because it is not available on Leap 15.4 repositories yet.