pp dropping in..?

Do they walk in while you are on the phone with them or after? Are they townies or playable sims?

I have this issue too. It occurs during the phone call. From what I understand the game spawns in the sim you're talking to but hides them to make the conversation happen. As of right now, the hidden sim will often bug out and when the game resets them it causes them to appear on the lot, as they are no longer in "invisible phone call mode" essentially.  It happens both with sims I"m calling, and sims who have called me randomly.

They don't  walk in they just appear while on the phone w/them and yes most are the townies