Can’t see it mentioned in the thread. Is Shield simulating physics or solely relying on the PMC? There are cases where you cannot (and should not) have both.
When the projectile hits something for the first time
How many times does it actually Hit - as hits can be temperamental and can trigger more often than one expects. Are you counting them or eyeballing it?
there isn’t an issue with the vector calculations
Irrelevant here but you can replace the - and Normalise nodes with Get Unit Direction.