Hi All (Especially Crin! It's been years since I've posted but I am just now joining the Sims 4 era!!)
I wanted to share I have this same experience with Planet Honey Pop.
Things to note:
1) I modified the building into a high end fashion retail lot. I moved the outdoor top floor entrance facade center with the building to make the entrance area flow with the community area tha features to symmetrical tree beds in front of the building.
2) As I Opened for Business those 2 days were snowy dark days. The lights inside didn't seem to do anything. They did in the bathrooms tho.
3) Found that the "facade over hang" over the front entry porch was open to the interior with no floor tiles. The game wouldn't let me add any which I thought was strange, so I improvised and moved the wall to enclose the space.
**It was this action that ultimately resulted in me obtaining the snow on interior floor problem like in this post**
4) This worked and the lights came on as they should. The issue was that this was when the snow on the interior lowest level floor showed up.
5) Since I started sims 4 on the 1.69 patch I had platforms from day 1. I used them to building display window cases in the front of the building.
I wanted you to know the two things I did differently that ultimately resulted in the same glitch.
Speaks volumes that if I removed one wall pane to outdoors along a floor tile with no platform foundation, the interior snow disputes even tho the space is open to outside.
hope these items help you! I'll keep working on a work around because I love this lot as a high end fashion store in the fashion district. Makes sense. lol
Thank you for all the work you do Crin!!!! 🙂