Casting To AnimBP instance Failing

I have a Skeletal Mesh with an AnimBP assigned to the component:

I have a timer which is attempting to update a variable within the AnimBP:

At runtime this is what is being casted to, bear in mind that the AnimBP named PumpAnimBP in this case is a child of the AnimInstance class. The cast promptly fails.

The animation works within the PumpAnimBP and everything else seems to be okay, The cast just fails.