Static Shield, Grenade Barrage, and multi-hit attack bugs

[bethekey.8314]

I've always been under the impression that each melee hit into static shield will stun, but apparently there is an internal cooldown or it's bugged. See video below:

It seems like not all hits for multi-hit attacks count as separate? This resembles an old video of mine about grenade barrage and blind:

It's very inconsistent.