I think something like this is happening.
On server start all the loot gets distributed over the map. Building 1 gets it first, then building 2, building 3, building 4, building 5, etc.. All in a chronological order. Building 1 is often right next to building 2 and building 2 is almost always close to building 3, etc.
Everytime an item spawns it deducts that item from the loot table making sure a single item cannot spawn too many times in the world thus making it a real economy where they'd have an actual fixed number of each loot item in the game instead of spawning everything by chance like they have been doing until now.
For example if this was a loot table:
+ Clothes - 100x Wool coat - 100x Grey hoodie - 100x Pink dress - etc.
+ Food - 100x Baked beans - 100x Canned peaches - etc.
+ Weapons - 100x Makarov - 100x M1911 - etc.
The problem now seems to be that instead of randomly picking an item from the loot table to spawn, it picks the one on top that is still available. Resulting in building 1,2,3,4,5,6,7,8,9,10,11,12,13,etc all having the same kind of loot since the items still have spawns left according to the loot table.
Presumably the function that should randomize the picking of the loot either got broken or was forgotten.