If you're using track day for traffic, try deleting "fast_lane_payloads.bin" in the following folder:
content->tracks->shuto_revival_project_beta->shibaura_pa_traffic->ai
Also disable "Cache generated payloads" under Settings->Custom Shaders Patch->New AI Behavior.
Note that it will still freeze after this, but if you wait 5-10 minutes it will eventually load now. This worked for me.
If that still doesn't work, try 2REAL with traffic planner instead on the Public Testing Build of the map. I hope this helps!