This is a known issue with outdated mods.
Map Reloading Issue
https://answers.ea.com/t5/Technical-Issues-PC/PLEASE-READ-Map-Reloading/m-p/6158906/thread-id/95485
To test this, move your mods folder to the desktop, clear your game cache and delete the localthumbcache.package from the Sims 4 folder to help with troubleshooting. Try playing the game again to test. If it loads okay, it may be that some of the mods/cc have become outdated.
How to Delete Cache Files
https://sims4.crinrict.com/en/2014/09/delete-cache-files/
Try the 50/50 method:
1. Move all the mods and cc out into a temporary folder on the desktop.
2. Move a few files back at a time. Load the game each time to make sure it loads and everything is good.
3. Delete the localthumbcache.package from the Sims 4 folder.
4. Repeat steps 1 - 3 till there is no more files to check.
** While your testing, don't save the game. If you find any problems, delete the mod or custom content file.
How To Find Problem Mods and CC
http://simswiki.info/wiki.php?title=Game_Help:TS4_Finding_Problem_Custom_Content
