No worries what so ever, I have a big part in messing things up. The said file is in the Sims 4 folder and nowhere else.
So, I have done some play testing with a family that had a problem with uninvited guests. After deleting the localthumbcache.package file I could see that the problem was gone. From this family at least... At first it looked like the action did block all guests as a few in-game days did pass without a single visit but slowly the friends found their way back to my sims. I did check all guests, both the one who was greeted by the door and the ones who walked in themself, and the action to send the sim home was always there. Now, I don't know if the problem have moved somewhere else but let's hope it's gone.