UE4 causing zombie process on mac

Not sure if this is in the right place. Please point me in the right direction if not.

I’m having an issue on my mac with unreal engine. 4.10, 4.11 and 4.12 leave zombie processes when quitting. I know this doesn’t take up an resources and it’s the parent process that hasn’t received the quit signal but what is causing this? when this happens I can’t reboot my mac without using a hard shutdown.

Is it a ue4 problem or a problem with my mac?

Does anyone know how to resolve this?

What I mean by zombie process is I get multiple instances of UE4 in my dock that state “Application not responding” and force quitting doesn’t work. They don’t show up however in Activity monitor buy they still prevent the computer from shutting down.

Any help would be appreciated.