Help with diagnosing an issue between Leonardio and Pro Micro

Hi all.

Weird issue.
I have a sim rig with motion and a dash button box.
Button box runs a Pro Micro with generic sketch.
Motion is SFX 100 on a Leonardo.

Prior to the motion I did not have this issue. And do not have the issue when the motion system is off.

The issue most notable in iRacing when you can see the pit commands being issued in the command box.
Issue is the button box throws random commands that are issued to pit commands assignments.

I have changed cables thinking it was a cable issue.
I have tried to reset the pro micro to load a different sketch however unable to do so.
I have double checked my wiring to the pro micro.
I have changed USB ports from 3.0 to 2.0 and back

Is it common to have a conflict. Is there an easy way to sort it - is it a clash of libraries?
Can you have multiple arduinos hooked to a PC? One is on Com4 the other Com13.

Thoughts or ideas or someone encountered similar in the past?

Cheers.

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