Volume keys require shift to activate

Question

Sometimes when I reboot my computer, my volume keys require the addition of shift to fully activate. I'm using a Purism Librem 13 V4, and running elementary OS Juno Linux. The volume keys are in a strange place they use the + and - keys with the fn key as a modifier.

The factory-intended and preferred behavior is

volume-up   `fn+=`
volume-down `fn+-`

the problematic behavior is

volume-up   `fn+shift+=`
volume-down `fn+shift+-`

I'm new to diagnosing problems like this but I'm not afraid of my console. Any pointers on how to go about investigating this would be appreciated.

Thanks