I have a question concerning the grace period between stuns and the spell negation for Banshee's Veil.

So a Nunu with BV ults and Udyr hits him with Bear Stance.

The first hit breaks BV's passive, so it negates the stun. Since Nunu was never stunned in the first place from Bear Stance's stun, is the grace period still applied?

Or does hitting Nunu with BV twice still break him out of his ult?

I would like a confirmation since an enemy Nunu broke out of his ult after I seemingly hit him twice while in Bear Stance.

a while back they made it so if a spell sheild is broken with bear the stun gets on cd for the person. so no its not posible to double stun. he most likely broke it himself, if not you would of seen him being stuned

I'm also curious.
If you want to test that in a practise match just invite me.

Nope, bear stance breaks a spell shield will also make the target immune to other bean stun for 5s, more than enough to pull the ult off.