Prevent Assembly Name to changes every run

As stated in the title i have that strange behaviour with the subsequent call

Assembly.GetExecutingAssembly().GetName().Name

My exe name is CoreService.exe, with the call above i get different response every time i call it eg :

1. Coreservice.exe
2. CoreService.exe
3. CoreService.Exe
4. Coreservice.Exe
5. Coreservice.EXE
6. CoreService.EXE

I get this behaviour working on Windows Server 2012 and only when i start my CoreService as windows service instead of windows process, anybody can explain why of that strange thing ?