I guess it is a bug of sorts, but not quite, so posting it here in Feedback.
Bane scrolls used by my Cleric have a horribly low DC of 5. LOL
A level 1 cleric with a bad Wisdom of 10 would have a DC of 10 (8+Level 1 Proficiency)
Addendum : I tried using it on Zombies with -3 Charisma saves, and they all succeeded :P
I will sell them.
Steam profile : https://steamcommunity.com/id/baraz/