New static strike stacks going away. Multistrike not gaining stacks

Static strike of gathering lightnings stacks on hitting an enemy are independent of each-other. E.G when I'm at 12 stacks and I stop attacking I can start losing stacks even before the timer goes to 0 on them.

Also when using multistrike I seem to trigger the lightning with each attack but I only gain 1 stack from the initial attack.