Left shift key outputs ± When I press the left shift key a ± appears on the screen. It is a bit hit and miss, but for the most part it happens.
Googling I found this seems to be a common problem.  The common recommendation is to reset the NVRAM and SRAM.

I did both of those things
It was recommended to try to reset the NVRAM several times so I did that
uninstalled my logic mouse driver (which uninstalled the related kernel extensions)

How can I get this fixed?
[EDIT] This is a 16&quot; MBP.  I am using a matias keyboard. It is a $100 keyboard from Fry's.  Pretty high end; the action is really good.
[EDIT] I plugged in an old MS keybaord I had laying around.  IT was working when I traded up to the new keyboard. IT throws garbage on the screen when I press the shift keys.
I went and bought a new keyboard and it works fine.
I had my friend plugin my broken keyboards and they have similar behavior on his Windows 10 PC (garbage on the shift keys).
I consider this solved but I am stumped that I have two keyboards with similar failure.
I would delete this question but there are other people reporting the ± on the left shift key too so I am just going to leave this question undeleted.