I beat Gears 5 on solo insane a couple days ago. Did not unlock the achievements for beating on insane and any difficulty. Chapter select says all acts completed on insane. My stats say Act II Chapters 1,2,3 have no completion and no collectibles found. So I bit the bullet and replayed those 3 chapters on insane. Finally I got my insane achievement, but did no get the any difficulty achievement. Not only that, my stats now say those 3 chapters were only completed on beginner difficulty. WTF Coalition.