[The sims 4] Luxury pack sims become stuck in selected mode, cant save game

I've seen this issue before and I fear it might be a sign of save game corruption.

• How long have you been able to play until they got stuck again ?
• Have you tried moving them out and back in via Manage World ?

I don't really have a solution for you though.

The fist time it happened within an hour, the second time within maybe an hour 1/2. I have not tried your suggestions yet, will do that now.

How could the game become corrupted without any CC or mods present? Do you think the devs messed up the pack data?

There's a lot of reasons for game corruption. Data that is not cleaned up properly or game crashes to just name a couple.

For me it happened twice so far but very far apart.

Do you maybe have a older save you could go back too ? 

Nothing that I consiously created...

I have moved the family out and back in now, played a bit and saved, it worked fine. No standstills so far.

If it should happen again, I guess my only solution would be to re install?

I don't think it's an issue that is saved by reinstalling. It probably has rather something to do with the save game.