I do not know if this is a bug but it is an odd behaviour. Once in a while I will go to a safe place in game like Devil’s Crossing and alt-tab out, go do something else that I am required to do (ya know - life) and I put my PC to sleep for a while. The reason I do this is because I do not want to create a new session, I just want to jump back in where I was. So… I come back to my PC bring out of sleep and alt-tab back into Grim Dawn. Then a group of achievements replay. This seems to happen all the time…
Anytime when I go do something else IRL (alt-tab out of Grim Dawn) and then go back into Grim Dawn, the same group of achievements will replay.
I hope this is more understandable.