During the tutorial (ship) only, I noticed that all weapon damages from party are bugged : they ignore Str and Dex bonus damages.
For example, Laezel was often doing 2 damage on Imps, which is below her minimal damage (Str bonus damage).
I saw this on current Youtube playthroughs, but also in mine.
This does not seem to occur after that first "scene".
EDIT/REVISION : turns out it is not a bug and Imps have Damage Resistances nonmagical to weapon attacks.
"Damage Resistances Cold; Bludgeoning, Piercing, and Slashing from Nonmagical Attacks that aren't Silvered."
[ which is half damage ]
https://www.dndbeyond.com/monsters/imp