It seems to me that this games pop-ups the same achievements over and over on player's profiles and activity feed.

It's not just achievement of two, I guess every time a user plays this game all the achievements that player unlocked so far will be displayed as if they were unlocked the first time.

I'm not playing this game, but a friend of mine is:
https://www.gog.com/u/PaterAlf

Since you probably can't see his profile unless you're a friend I've attached some images.

Hope PeterAlf don't mind.

Yes, it's completely bugged. For the first wekks that I've played it worked fine, but some weeks ago the achievements broke and now you get them every time when you play and and complete the first dungeon of that session. It's very annoying, because there's not just a handful of achievements, there are about 200 (which is stupid per se) and after the first dungeons it takes about 10 minutes before all the notifications are finally done.

Hope they'll fix it. Already reported it using the Mantis form for Galaxy 2.0. But maybe I should write to support as well.