Thank you Don and jotjotde.
I consider this issue closed, but wanted to add one more CLUE for someday finding the root cause:
After the first cycle, riding to drain the SoC for the next charge, I parked it at 41%. When I started it back up to move it to the charger, it displayed 91% SoC.
The missing 50% that magically disappeared 4 days earlier miraculously reappeared.
When I put it in drive it gave a status message ( I wish I took a pic to get the exact wording ), that said something like:
"Charge to 100% to allow for cell balancing and to Align SoC"
I did charge to 100% (which I typically do every 500 miles or so (80% SoC my typical overnight charge)).
And again, no error codes were found in the diagnostic screen (haven't check OBD2 yet, but don't expect anything since I didn't see an actual error since getting un-stuck from 0% SoC).
Thanks again,
Mike / firmware