I've noticed something similar while on FK.

The main thing I noticed though is that a double strike would only register as one strike, but then the next champ's attack would make the total correct itself.

For instance:

Juliana hits FK twice along with a WM proc, the shield only drops one stack.

Skullcrusher hits FK once, the shield then drops two stacks, correcting the missed stack drop from the last hit.

Oh I see now, so this is more of a visual glitch, the shield damaging still happens. That makes sense 

I’m getting something similar only it’s not just visual yeah the counter for the shield is off at times but when it opens it still acts as if it’s closed reduced dmg and no debut will land.

What about warmaster/giant slayer totally breaking block revive skills if they proc? Ice golem says hello!