[RESOLVED]
My keyboard is fixed. The fix is to open it up, clean up contacts and reset the ribbon connector(s) for any keys glitching. I had to do this twice, but the second time is holding good. I watched 3 or 4 YT videos about the issue, which taught me how to disassemble the keyboard, remove the membrane, clean the contacts, and remove then reset the affected ribbon connector for the trace array that controlled my numpad.
If you are having a similar issue (multiple characters being output for one key press), then read on..
This is not a software or firmware issue, so don’t go down that rabbit hole. It’s electrical connections and circuitry. I believe the ribbon connectors for the 4 or 5 different key arrays do not make good connections - therefore vibrations and/or jolts to the keyboard can knock them out of critical alignment.
Search YT for ‘Cynosa chroma typing fix’. Make sure to watch any that go over ribbon connector cleaning/resets.
None of these keyboards are likely under warranty any longer, so you have nothing really to lose. The fix can take up to an hour or longer, but the bulk of the time is digging out all of the screw covers and unscrewing the hidden screws (there’s 15).
I’ve taken apart thousands of things in my lifetime, so this was a breeze for me. Doesn’t make it any less aggravating, though, and I didn’t enjoy wasting my entire night - but ultimately it IS fixed (for right now).
YMMV, and I’d be happy to assist anyone who is having any issues doing this fix.
Cheers