It would appear your library is yet to refresh.
Why would it take GOG a whole week not being able to simply change a few database entries? Because thats all there is to do.
It is not just about changing your access to the database, it is also about your browser entries changing to reflect that. Clearly the original files still existed, but after my library got refreshed, I lost access, because what I had access to had changed.
You have clearly not had your library refreshed, which might be as simple as you logging off and then back on again, or using the GOG refresh option, or something else gets changed in your library that necessitates GOG doing a refresh for you.
A refresh happens to me quite often, without logging out and without using the GOG refresh option. I can see the result of that, like many others, when the Seven: Enhanced Edition game jumps back to the first entry in my library. There is even a thread here all about that