Lutris not shutting down properly?

System information

When I play a game via Lutris, I find a while later that my laptop is running very hot. When I shut the system down, it tells me that two Lutris processes per session are still running (eg if I’ve played one game twice since last rebooting, there will be four listed processes). I haven’t yet found a way to find and kill these processes without rebooting, or to shut Lutris down cleanly without generating these files.

Can anyone help with this? I don’t want to have to reboot every time I do anything in Lutris…