I know issues like this can be frustating, but we are doing our best to find this. Sadly, this issue is not affecting a lot of users so it is proven to be hard to pin point. Saves would be very helpful so, if anyone can share those with us, that'll be great.
I am having this same exact issue and repeatedly. Has there been any resolution to this issue? On occasion I can leave the house (come back) & event planning will work and let me invite more than one guest (which currently with whatever bug this is doesn’t even let you plan the event because you must invite two guests) since I’ve done the whole leave the house thing a couple times it’s stopped working again. So now I’m back at square one and can’t host an event. Which is frustrating.
As posted above, we are in dire need of save games. We have not been able to reproduce this at our end?
Would you be willing to send us yours?
Here you can find the instructions: