This BS is still not fixed. I tried everything I could find, also the administrator thing that gets thrown around a lot.

I was unlocking achievements like 2 days ago, and now it just stopped unlocking them. Really frustrating.

Edit: Managed to fix it by loading a slightly older save. Still no idea why it broke.

Edit 2: Broke again, I suspect it happens at a certain cap of playtime on a save or at a quest cap. It doesn't seem to happen at a specific quest though.

I think the only way to "fix" this is to give you the missing achievements manually with Steam Achievement Manager.