[bug, csc] Common Cold passive does not trigger properly

This is probably because the triggered part of the card isn't Poison+1, just Poison>=1.

Since the card dizzies at the end of ability resolution, this means that the target is first getting Poison+1, and only then the other poisoning ability triggers and does nothing because the monster in question is already poisoned.

So, the card is behaving exactly as written, but the way it's written is stupid.