Bristle bill is buffing greggs and own cretaures

Iv noticed that If something triggers bill to reinforce on greggs turn he will activate and buff all creatures in play, this also happens on your own turn to. It seems anything outside of landfall triggers this unintended effect. Iv attached a battle log showing it triggering on greggs turn and buffing gregg on my turn and the deck I was running incase it helps with testing :)