I was doing some cleaning from my mods folder (which was soo necessary at this point lol things were starting to get out of hand lol) I noticed after removing some files, I was unable to load my current household. It was stuck in that infinite loading screen bug??
Long story short, it was an Infant Playmat recolor (this is the one I used in particular) that caused the infinite loading screen bug for me. Without that CC, a last exception was prompted for me that read:
"T:\InGame\Gameplay\Scripts\Server\developmental_milestones\developmental_milestone_tracker.py"
After doing some searching, it appears that any infant milestones that were achieved using that particular playmat, will be linked to that playmat. So without it, your game (or at least for me) will not be able to read any of infant milestones!
Wild, huh? I didn't think a simple recolor would cause that kind of a bug. I thought it would be helpful to share this just in case anyone else was experiencing any of this weirdness.
(Also, I'm not saying the creator of the recolor was aware of this happening or even knew this would happen, but I'm sure this an issue with the original file to begin with)