Setup:

Advancement with player_hurt_entity criteria, runs function when triggered

This function checks, if the hurt entity (I test for HurtTime:10s) has potion effects.

Issue:

The function always says that the entity has no potion effect, even when using arrows with effects.

Note: I didn't use tipped arrows in the inventory but changed the NBT data while the arrow was in the air. I guess that makes no difference but I wanted to mention it here in case it matters.

If I check for the same thing in my tick function, it works, meaning the effects do work and get applied to the entity in the same tick.

The advancement reward function seems to run before the potion effects get applied, although both happens in the same tick.