Why Source files are created in intermediate folder?

Hello. I have some problem. The problem is that source files(##.target.cs, #editor.target.cs etc..) is created at intermediate folder when compile by visual studio. resultly, ‘Target.cs at my project source folder’ and ‘Target.cs at intermediate source folder’ is conflicted. since this problem, i can’t build my project and run editor.

this problem is only occurred when contain plugin(Gameplay Abilities) in my project. if i except that plugin, problem is not occurred.