Increased Attack Damage not applying to some Crossbow skills

Some crossbow skills do not benefit from increased attack damage from the skill tree despite having an "attack" gem tag. Tested affected skills:
- explosive shot
- fragmentaion rounds
- armour piercing rounds
- maybe more

How to reproduce:
- open skills view and check damage value on skills
- allocate a node that increasea attack damage. For example the "two handed damage" nodes near the mercenary start. Or socket a jewel with x% increased attack damage.
- Check damage values of the skills again. They don't change for the listed skills. However damage for "crossbow shot" changes, grenade skills also change damage values.

Cannot test if this is purely an UI issue or if it really doesn't increase the damage.