Melee block blendspace


I want the character to block melee attacks and hold his weapon up, down or sidewards depending on the hit direction automatically.
To do that I made a blendspace:

Inside the AnimBP I try to lerp between the current BlockAlpha and the target BlockAlpha.
So for example if BlockAlpha is currently at let’s say 0.5 and since the attack is coming from above, the character should hold his weapon above his head, thus BlockAlpha
needs to be a value of 1.

But no matter what I do, the value lerps to the target value very slowly. (I tried different values for InterpSpeed)

So where is my mistake?