Hearing people talk on my AirPods Pro when texting

The other night I was texting (iPhone 13) with my bf (iPhone 15 Max) I had my old AirPod Pros (1st Gen. but only in use for 5 months) so these are iMessages. I could hear what was going on in the background when he was texting me! It was exactly what he was talking about with his friends. I heard them all. It freaked me out and now, I was texting and when he was responding I heard a notification-as if it a notification that he was responding because the (…) came up as he was typing. Is anyone else experiencing interference or weird behavior with iMessage?