Oh, thanks for the warning. I almost missed it as it did not show up on updates it seems. Recently GOG was screwing up with a couple of updates, sadly.
It is not the first time a NIS game got such a issue with "all of a sudden" disappearing DLCs, usually the ones from the launch. Not nice to see, it is happening once again... for whatever reason. It appears the server, all of a sudden, is "removing" the "launch-tag" on those accounts.
Not sure how fast this issue will become solved... but all a customer can do is handing out a ticket.
I do not know what they did but the installer at least is totally screwed up. Not even a "tagging" issue, so much stuff has been gone missing.
Let me show you what i mean:
https://ibb.co/RgL1Z6M Decreased quality on attachment because the forum is not capable to deal with PNG.
The only possibly working solution for now is to use the patch, yet not sure it will work for all the DLCs involved.
If unsure, simply leave the game at the old version for now. The fixes are not critical and most users may not experience those issues.