Switching scenes saves assets?

I am curious to why all assets (150 pieces) has to be saved everytime I switch between two scenes in the same project?

Does this have anything to do with my Editor/FBXimporter.cs class making unity triggering this or why does all assets have to be saved/reimported everytime I save/switch scene?

I use a great deal of fbx models, imported with the original process, and I have no scene save issues. I can freely switch between scenes without the need to save. Is it possible that your script goes through all your imports and alters them in some manner when you enter scenes?