I just had this happen in my current save. It was someone named Grimulf, someone whomst my Sim has never met nor do I have any idea who he could be. I saw the pop up, though, and was definitely a little confused.
I am currently running with less packs downloaded than I usually do, though it did not start until I added the Master of Grudges reward aspiration. I'm not sure if that's just a coincidence, though. I know that caused other issues that I already marked on a separate thread. I am including a screenshot for the packs I have downloaded at the moment.
I have no mods or CC, and I have not had them in months (and never in this save).
The Sims Team
