Sorry i thought it was global layers we were talking about, in my case was using global objects on global layers and i think that was causing the replication,
but i am also dealing with a case similar to yours and yes the program is creating global object on every layout (on a random layer when similar layer does not exists), in my experience it is creating on random layer because in my game the layout with global object has it on layer number 8 but when i change layout it creates the global object on layer number 1 (while the layout has three layers(0,1,2)) it should technically choose the top layer as default but it didn't so i think its random, i could be wrong though!