Unknown people in party

Every day when I login to PoE for the first time, the player LALALALLALALALA always appear on my party as "offline", and then suddenly disappears. What's weird is that it only happens ONCE every day. Around 2:30 pm time, forum time (approx 3h ago)
I have no idea who that is and never talked to or partied with. I suspect its either a bug or my account has been compromised, but nothing in the account is touched so i suppose it's just a bug