This is an older issue that has been marked as resolved, however upon creating a datapack in which some summoned mobs rely on this, I realized that it still doesn't work. Summoning wolves using this command:

summon minecraft:wolf ~ ~1 ~ {Attributes:[

,{Name:generic.movement_speed,Base:0.5f},{Name:generic.attack_damage,Base:20.0f}],Health:30.0f,CustomName:"\"Grave Assassin\"",Silent:1,Tags:["getplayer","summonedBase","summonedGA"],ActiveEffects:[\{Id:14,Amplifier:0,Duration:999999}]}

The invisibility, speed, and health modifiers work as intended, however, whether splashing the wolf with a strength II potion or summoning one in with modified attack damage, the wolf's damage remains the same.

Steps to reproduce:

1. Summon a tamed wolf or tame one using bones

2. Let wolf damage mobs

3. Splash wolf with strength potion or edit generic.attack_damage attribute to increase the wolf's damage

4. observe that the wolf does the same amount of damage as it did previously

I hope this can get fixed soon, my datapack and the summoned mobs really rely on it. Otherwise, they all do the same damage, which completely defeats the purpose