Does this happen with ANY couple you send to that lot or only a specific couple? Does this only happen with dates at Londoste or do you have other problems with the lot when not on a date?
I remember someone posting a story (sounds like Sagana's post
) about a problem like this. I believe what caused it was the person was saved while on a lot that wasn't their home lot and the game kept getting confused. Once the lot was re-entered and saved without the visiting sim, the problem went away.
Example: on Jane's lot, Jane invites over John. While John is still on the lot, they game is saved and the lot is exited. John's lot is entered, he calls Jane and asks her on a date. Everything is fine until they show up on the community lot where the player gets the message you got. Returning to Jane's lot, sending John home, re-saving solved the problem for that poster.