"Unknown region: region _Residential_BayArea" On San Sequoia Resident Profiles

@Sims4Ever2022 I don't have any Mods/CC in my game, including MCC, and in my game when my Sim went and met meet Christopher Michaelson, in his Sim profile I only saw what is below (not his home residence), so I assume that this additional information that you're referring to (where the Sim lives) is coming through one of your Mods, perhaps MCCC from what you say. If this is an aspect of MCCC or a different Mod that you've added to your game, you could look for if the Mod(s) has/have updates that since the release of Growing Together, since both Christopher Michaelson and the San Sequoia world were added with that pack. Perhaps they have not updated the code in the Mod(s) to identify San Sequoia yet, or perhaps they did and you need to add a Mod update(s) to add this function to the Mod.

Edit: I see that MCCC has an update that's required for Growing Together, so you may want to add that update, if you haven't already.

I checked, and I have the latest version of MCC. I uninstalled and reinstalled it anyway, and repaired the game, but the glitch is still there.

@SheriGRI Use MCCC too, but in my Game a Sims Profile looks like yours in your Picture.

@Sims4Ever2022 Since @666_Carbide_666 is not seeing the issue with MCCC (I'm assuming they have the most current version) you could try the following. This should help us know if the issue may be something cached in from before the update of the Mod, plus it will tell us if you can confirm the issue isn't showing without any Mods/CC or the cache file in the game. 

You can make a backup of your game first as follows: 

Exit the game. Move the Mods folder from your "The Sims 4" folder [Documents > Electronic Arts > The Sims 4] to your desktop (save it for reference) and delete the localthumbcache.package file in your “The Sims 4” folder. You can then test in a new vanilla game save to see if the issue is gone.

If the issue is gone, try adding the updated version of MCCC and see if the issue is still gone. It's also possible the affected world may need to be loaded without the Mods in, but we can check this first.

Btw... do you have any other Mods or CC?

@SheriGRWhen I was writing my answer yesterday the newest MCCC in my Game was 2023.1.3.
(before I started my game there was no Update)
I've Setup my Game (MCCC) to show a message if something happens in Game with unplayed Housholds.
So I got ingame messages if someone (a NPC) got a new Job, Got Pregnant, Move in in a house.........

I Got messages about Neighborhood Stories too and when someone move in in a hous in San Sequoia, the game shows a message "Household XX moved in Eucalyptus Lane in Unknown region: region _Residential_BayArea"
But i am not sure is this a message generated from game itself or from MCCC.

Today I will check it out with MCCC 2023.2 and will test without MCCC.

That means: In a Sim's profile, I don't have the Information where a Sim is living. Only in the Notifications on top right corner in livemode.

In my Game it was possible now to trigger an ingame message about Neighbourhood Storys with the option on the Mailbox.

The Ingame message shows the correct text.