How to run multiple instances of GeckoDriver that won't cause issues with focus?

[Kabone]

I have a project where I would like to run multiple instances of a the geckodriver, to allow for multi threading. The issue is everything works but randomly browser stops interacting on certain browsers. I am using runnables in java for handling the multi threading. Also each instance is using its own exe but still having issues. Can anyone point me in the right direction?

I can include any info that may be needed 

[Kabone]

Figured it out. Was an issue where the thread was failing to find an element and it wasnt quiting correctly.