I had this bug show up after the Chinese update (I play with KB+M) and so used the fix posted by Sarafan.

This bug has also been reported in the Divinity forum with a link to the fix too;
https://www.gog.com/forum/divinity_series/skill_books_how_do_i_know_what_level_of_aptitude_they_are

Yeah, I guess GOG should just remove the localized versions altogether. Since people call it a game-breaking bug, those localized versions are completely useless. Too bad for Chinese and Korean players, I guess. Maybe they should learn English like the rest of the world (I hardly ever see Finnish-localized versions of games, and I am not expecting them either).

Most of the blame in this case should go to Larian, they fucked it up, and still haven't fixed it.

EDIT: Ok now I read that apparently it is affecting only some players, so it is more complicated than that...

Even Chinese and Korean languages should work with the mod posted above. So it's not that bad.

That's for sure. I have no idea why Larian hasn't fixed this bug as of now. If the solution is as simple as using the file from older versions, this situation is really hard for me to understand.

UPDATE ABOUT "FOR THE KING"
===========================

Here is GOG's reply to my ticket:

"I'm sorry for the late reply. We're currently overwhelmed with work.

We've taken a closer look at the game and indeed there might be a problem with it as described in your message. We've informed our product team about it, they will reach the developer and try to solve it.

If you are not satisfied with the current game and don't want to wait until this will be resolved, then I can offer to convert this purchase to wallet funds, that you can use towards buying a different games.

Alternatively, I could issue a cash refund back to the original payment method, after you agree to fill out a questionnaire (which I’d then send in my next reply).

Keep in mind that cash refunds take a couple of business days to be fully processed on both sides, whereas GOG Wallet Funds get assigned right away."

I opted for a wallet funds refund.

I will post here if and when MaGog notifies me that the game has been updated.

UPDATE ABOUT "DIVINITY: ORIGINAL SIN - ENHANCED EDITION"
======================================================

Here is GOG's reply to my ticket:

"Providing download of older installers is complicated for us especially now when we are working remotely. Adding the old version installer as bonus downloads is also not the best option..
I see that you have installed the Galaxy Client for ticket #601905, please use it to rollback to the 2.0.119.430 (A) version.

To import individual games, please open the Galaxy Client, open your Library, click the game, clicking MORE > Manage installation > Import folder and select the game's directory.
After verifying the file the game will be imported, to use the rollback feature click the game, click MORE > Settings, here disable the "Auto-updates" feature and select the older build to install.
After the game is "updated" you can remove the Galaxy Client.
I apologize for the inconvenience."

================================================================================================

Here is my reply to their reply:

"I am sorry, but using galaxy is not an option for me.

I do not plan to play the game now and galaxy only updates the installed game, not the offline installers themselves.

I travel a lot around the world (sadly, not at the moment), especially to regions that have limited or no internet access. I therefore depend on my GOG installer backups (stored on a portable HDD) for access to my games.

Could you please try again to furnish me with the older version offline installer?

According to Larian (https://www.gog.com/forum/divinity_series/dos_skill_book_level_not_showing/post2), this is something you were willing to do in the past."

I got a similar response : "I'm afraid that rollback feature is only available for GOG Galaxy users. In this case if you wish to rollback, you should install GOG Galaxy".

So it looks like GOG are now refusing to provide the older non-buggy installer version even though Larian have confirmed they did so in the past when people asked. Very sad to see GOG go downhill like this.

UPDATE ABOUT "DIVINITY: ORIGINAL SIN - ENHANCED EDITION"
======================================================

Here is GOG's final reply:
"Unfortunately we no longer have those download links prepared. The offline installers for this version were purged, when there was a content system cleanup, and would have to be generated again.
If I had access to these files I would have made them available for you.
Sorry for the inconvenience and hope for your understanding."

I closed the ticket.

Thanks for these updates, mrkgnao! Though it is very disappointing to see such responses. That is crazy if they purge backups because what happens if a new version or new W10 update breaks compatibility?

Also wanted to note that the defenders of the Galaxy are awfully quiet towards this topic. Seems like they can't "just use a python script, it's no big deal" their way out of this one.

What the fuck is this ? I would understand if they are overworked but i guess something like we will get around to it when things has calmed down would be nice but if they will not even bother asking Larian for new files so they can upload again so it works properly then fuck it.

Replace whoever makes these idiotic desicions already if this truly is the final decision on it.

I will stay out for now, there's a reason why i usually avoid criticism threads since i easily go overboard and probably end up banned forever.

Thank you very much for following up, mrkgnao.
Yes, and surely if they have the files available for Galaxy's rollback feature they could just use those to generate an installer.

That's exactly what I was thinking. "Hey we keep deleting our last known good backup installers in blind faith that games developers can never make mistakes / introduce regressions!" does not sound particularly forward thinking, especially where the devs may either not be in business or simply be too busy working on other projects to drop everything and re-upload older builds they already gave to GOG once.

Obduction is another example. Although Obduction never had rebindable keys in-game, being an Unreal Engine game you could still rebind them outside the game by editing input.ini (which worked from v1.0 through to at least v1.6). However, since the newest patches (v1.8.*) they somehow managed to break the game enough so that if input.ini was edited, you cannot move at all in-game without ending up quitting and deleting the whole input.ini file. RIP left-handed keyboard & mouse players:-
https://www.gog.com/forum/obduction_r/changelog
https://www.gog.com/forum/obduction_r/how_do_i_revert_back_to_142
https://steamcommunity.com/app/306760/discussions/1/1643170903483832677/
https://steamcommunity.com/app/306760/discussions/1/350541595104253714/

Thanks. Added to OP.

Redirecting you to an "optional" client which does not even allow to download an offline installer for the not broken game version and closing the ticket, that's bold. Apparently the "stellar support" is not anymore one of the reasons to buy on GOG.

That's not even the case. Obviously they still do have the files of the bug-free version, otherwise Galaxy would not be able to roll back to that version. They easily could recreate the old installer as being able to create the offline installers from the Galaxy files was the whole point of switching to the "sliced" installer format.

It's true for some games (DOS:EE) but not others (Obduction). Eg, the "How can I roll-back" thread for Obduction could let you roll-back to 1.4.2 in 2017 (from 1.6.4), but now in 2020 you can apparently only roll back to 1.8 (still buggy) from 1.8.4.1. So even for Galaxy, for some games GOG do seem to delete all previous versions beyond the last 8 months, suggesting that the developer has to re-upload them again (because they can't create a 'last good' backup installer from the Galaxy repository of v1.6/1.7 and earlier if according to the changelog thread, they've seemingly gone and deleted those too).

This topic is another reason I wish GOGmixes would be brought back. As a customer I feel I can't rely on the "official" story, when stuff like this is going on under the radar. Just like other, perhaps more benign, topics like "The What did just update? thread", it seems we have to rely on each other for some of the information we really need.