As the summary says, sometimes, maybe 5% of the time, Stop All Jobs will kill my entire login session. I am connecting to a CentOS 6.8 machine from Windows 10 using ThinLinc (which uses TigerVNC), where I run KDevelop via the AppImage distribution.
Although it seems unrelated, FLHerne (on IRC) did mention that the symptom is similar to this bug #379093 in kio.
I don't use KDevelop through a VNC session any more, so it's unlikely that I'll ever be able to add more information.