I came across this issue while playing yesterday. Almost every time I went on a date with a sim to a different lot the date would seem to turn invisible after it ended but they where still on the lot and my sim would still try to interact with them. If I tried to focus the camera on said sim it wouldn't do anything. This was the case for both the lovestruck dates and normal base game dates. The only way I was able to remedy the issue was traveling to another lot.
I have all the packs and the lastest version.
