No you aren’t understanding, you could just be lying if you are teammates. How are you not seeing this? I’m not even saying it’s true I’m just entertaining Juliet’s idea but you are missing this completely.
you investigate sall. That night he joins your team. So either you didn’t actually investigate him because he joined your team or you did as he joined your team and then possibly lied about results to confirm his claim. Or he is potion master in your team so it matches regardless.