Please fill in as much as you can :
Date and Time : 22.04.2016 - 04:40 am
Game Control Mode (Keyboard/Joypad/Mouse) : mouse
Where it happened (which map, which quest, which npc, etc) : Tiltas Valley
Bug Description : I earned the achievement “The Greatest Heir”, opened Adventure Journal and see 251 earned achievements 
UPD. Some time later, I opened Adventure Journal again, and there are 506 earned achievements 
I see, that this number is accumulating by killing monsters.
(letting us know what you were doing before, during, and after the bug happened will help us a lot)
Screenshots / Video :
(attach screenshots or videos regarding the bug)