As you can see it always comes from the same townie not from npc. Sometimes other townies also do this but mostly it's from the same townie. I have remove all mods still the same. I haven't tried doing sales on other lots but all the sales the issues happen is in my sims house.
What traits does the Sim have ? Have you tried deleting them through household manager (if you don't care about them)
He has grouch, Erratic and Foodie. Whenever he comes over I will have another sim try to chase him away or distract it so he doesn't come to the food but eventually there will be another sim that will come over to spoil the food
I've seen someone say it may be related to the grouch trait. Would be great if you can check if all Sims that do this have that trait.
I don't think the interaction as such is a bug .. just overly excessive in your case.
I haven't had the time to test out yet. Will see if it has anything to do with the grouch trait
