[matthewmwps]

To give a simple TL;DR before the post even begins:
If you have two parries, the lower priority parry should be allowed to activate for attacks which don't apply to the higher one.

For the more detailed explanation:

My understanding (from a small talk with others mind you so take with a grain of salt) is that parry skills have a priority system.

If you have multiple, the game will always default to the highest one. If you have stalemate for example and know no pain, stalemate will always be the parry the game uses due to its higher priority.

This prevents multiple DR skills stacking on each other to make a high damage move essentially become zero.

But the system doesn't care about conditions. It always uses the higher priority.

So if you're attacked by a weapon that KNP applies to but stalemate doesn't, it doesn't matter. KNP is completely ignored over stalemate.

I think in those circumstances, the other parry should be able to attempt a proc. This would apply especially to something like holy shield, which is omi-dimensional. Should you have stalemate equipped, holy shield will never apply it's parry even if you're attacked from the back.

Obviously if the higher one has the conditions needed and fails its chance (i.e. stalemate CAN parry the attack but does hit the percent chance) it shouldn't look for other parry skills.