[Neus]

It does. It functions the exact same way for momentum penalties as it does for momentum bonuses; it's tracked by the weapon. If you attack with a weapon that deals on-hit damage that the enemy is weak to, you will get a momentum bonus, even if you didn't critically hit. I'm not really confident that elemental damage from the weapon and critical hits from the weapon should be tracked separately because that starts a whole chain of stupidity; if the weapon itself deals damage that the enemy is weak to, and it has an on-hit effect that deals damage the enemy is weak to, and the material the weapon is made of triggers and deals damage the enemy is weak to, and I critically hit, should I get 4M? Probably not.

That's my opinion, but feel free to say if you disagree.