I really did that. Never wanted to start it all over - went back till the end of Chapter 2 and made a new start from there but received the same result. The same time, while checking the installation on my Steam account, I got a message, that the version (Director's Cut DLC) is not available in my region - however I made the purchase on Steam via a Steam offer. Also tried to move the savegame files to one on my friends' PC, all the same.
So from that I assume, that the save game is corrupted as a result of a faulty Steam installation (one of the patches is not available in my region).
While going through the game I have also seen cutscenes with the GOG version that never played on the steam version, even by fetching the previous save game from near that point. Might not be a general problem with the Steam pack, but a specific for my region (whatever it is, I couldn't make Steam confess what is its assumption on that).
Curious...
If you don't mind, can you zip up that saved game and send it to CDPR Tech Support. I can't imagine it's a priority at the moment, but if there is something up with the Steam installation, they'll probably want to know.
Before that, though, have you recently moved? Did you open your Steam account in a different country? By "region", it means global regions: NTSC-U, NTSC-J, PAL, etc.
If you're using any form of VPN, be sure to disable it completely before playing anything via a platform front-end: Steam, Galaxy, U-Play, Origin, Epic, etc. That can be an issue both in terms of the game being able to communicate correctly with the platform, as well as a user and account violation in many instances.
Aside from that, I'm not sure how the game could claim you're in the wrong region but still give you access to the game itself. That shouldn't be happening.
