Even if you dodge you get poisoned. I dont understand the logic but that has been the case, and its not considered as a bug and wont be changed i guess. I think its because it is still counted a hit. If you are facing hidan roshi, killer bee team. Hidan creates 24 hits even if there is a dodger in opposition. But despite the count of 24, it doesnt trigger combo since the minato/masked man dodged. So its considered as a hit but doesnt add up to combo but poisons.

There was a long discussion about this, but cant find the post.

i'm sure poison gets delivered with full tai or half tai/half nin mysteries, not sure about standard attacks.

I donot guess it's a bug. It will cause poison on landing a tajitsu hit regard less of whether it actually hits or not. Take example of minato edo if you attack him even if he dodges the attack you will get ignited and taged