This is happening whenever we have a full household (8 NPCs + 4 playable Sims).
This was the household in my main account some weeks ago, four playable Sims and eight NPCs.
Lise is engaged both to Aria (playable Sim in the same household) and to Benson, a young NPC who works at the lab in Waterfront.
The game works as expected when I try to get Lise and Benson married. He is an NPC and will move in automatically to the household after the wedding. Therefore it's correct to remove one of the eight NPCs to make room for him.
Other cases described under are bugs.
1. Marriage between two playable Sims in the same household.
Lise and Aria are active Sims in the same household and are using each a playable Sim slot. If I try to get them married, the game asks me to remove an NPC for them to be able to marry. Aria is not taking the place of an NPC. She is a playable Sim and is using a Sim slot already. It is not necessary to remove an NPC in this case.
2. Marriage between a playable Sim and another playable Sim that belongs to a different player.
My playable Sim, Jeanette, is engaged to Guillermo, a playable Sim in my alt account.
When I try to get Jeanette married to Guillermo, the game reacts in the same way. It is asking me to remove an NPC. Guillermo is not moving in. These two Sims are getting married, but Guillermo is not moving in instantly.
I cannot ask Guillermo to move in until their relationship reaches level eight, and then I would need to have a playable Sim slot. Therefore it is unnecessary to remove an NPC.
3. Marriage between a playable Sim and a young NPC, both in the same household.
Robert is now an adult NPC and is engaged to Aria.
In order to get Aria and Robert married I had to remove an NPC. Both Sims are already in the same household. They are only getting married. It shouldn't be necessary to remone anyone from the household when they are getting married.
@SalixCat & @sparklypickle6 how has this issue been since reporting?
I have now tested the first two variations and the results are still the same. This bug is not fixed. I have four playable Sims and eight NPCs.
1. Marriage between two playable Sims in the same household.
Ragnhild and Denzel are playable Sims and none of them are taking the place of a NPC. This message makes no sense in this situation.
2. Marriage between a playable Sim and another playable Sim that belongs to a different player.
My Sim Karl is engaged to @Phantomlover1717 's Sim Bug Tester 😉 Bug is not moving in automatically to my Sims houshold. She is a playable Sims, not a NPC and a free NPC space is therefore not necessary.
I will test the 3rd case and post results as soon as possible.
