frostdemonstorm: Seems a bit different bug. I would suggest to report it to CDPR directly with saves attached. It surely more useful than report it to gog support.
Normally I would, but for some unknown reason I cannot create an account or use my GOG account to login to their forum to lodge the issue. I can't contact them to find out why and I figured GOG's forum was the next best thing.
From my searches around the NET I seem to be the only one that has seen this, plenty of entries describing the issue of the initial post, but nothing like mine.
Posted it on Reddit too in the hopes someone else may have seen the same thing and they might be able to post an official report.
I will try again with another browser later, just to be sure.
EDIT:
Figured out my login issues, 3rd party cookies settings! As soon as I set an exception in Chrome for all the GOG sites, my login details were used correctly.