I have noted situations in Solasta where you don't make those rolls and remain in stealth regardless
I think that if enemy has line of sight to you, you should get the roll. There is definitely no roll if you kill enemy with the hit, and I am pretty sure there is also no role if you are attacking from undetectable height (3 tiles higher then the enemy, I think). I remember there being quite a few instances where I was surprised not to roll, so there might be some distance issue.
