Glad you god it sorted out. I have the same problem on my settlement but my patience ran out before I could find the offending object.
Section out the build... and delete everything in each section save and try ....then next section save and try etc...until you narrow it down...and can start trying objects locally..
Imagine that i found the issue in the problem cell that was the main cell with most of the buildings (tall buildings fully furnished and decorated...)....
Now i have the other issue (other post)... where precombined generation isnt seeing certain texture swaps even though both in CK and in game before i generate everything works fine.. and here is the head banger..it only does it with vanilla walls and diner parts. The swaps i used are vanilla interior materials and textures from institute,prydwen...etc...