AI passive stun parried in AQ

Thor Ragnarok in AQ map 6 .. right hand side .. he parried him when I tried to intercept.. now its fine that he can auto block and parry, that’s his ability but then I got passively stunned !!! What’s up with that?

I have intercepted this guy before to get the corvus charge but never been stunned before. The global was Hurt Locker.

I don’t have a video unfortunately