NPC Sim invades home - inconclusive Cause (Patch 1.110)

I recently found something that was happening  and I did not realize it. I have a household in Sulani and I was in build mode doing whatever, and something made me click on the option to show the colored outlines of the building. Part of it was in blue meaning residential, and I noticed that parts of it were in pink I think it was, meaning the rooms were designated public as if for a small business. Not sure how this happened as to my knowledge I had never used this home for any kind of business. In this particular home I have not had a problem with people just coming in out of the blue and doing stuff, but I have had the problem in other households. I haven't had the time to go through them all and see if this is happening in those homes but I wanted to speak up about it in case it is part of, or could be causing the unwanted visitors problem. I have so rarely actually clicked to look at the colors of the building outlines and it was a fluke that caused me to actually see that. Here's hoping the problem could be fixed that easily.