Newb invader- Etiquette/aita Question

Just tried invasions for the first time today most them were pretty fun even when i lost but more importantly one of those i encountered 2 players sitting at a grace i was initially very wary, because a blue got summoned right away( didn't actually see him, but he did spook me) me but they seemed chill ( we exchanged bows) and one of the players mimic veiled but then that player started approaching me around the side as they summoned another Phantom

So I got worried he was trying to backstab me and smurf breathed killing the host + phantom 1 was I breaking, like some pvp, etiquette or something?

Rl200 is it matters