When applying weak point modifier though a player card(currently no card in the game actually applies weak point, I just modded in a new card), 1 stack of weak point is instantly removed, and no benefit from weak point is added to the attack. I used AddCondition() inside OnPostResolve of the card definition to apply weak point.
1. Add a custom attack card that targets an enemy, and apply weak point to them using AddCondition under OnPostResolve.
2. Use this card against an enemy.
3. You can see that 1 less stacks of weak points is applied to the enemy because it is consumed without the added benefit.