This question actually should be placed as a general question, not in 'Report a Issue'.
Anyway, I wouldn't call this a bug since:
- it's a logically and consistent behavior
- it's 'as-designed', means on purpose
- it follows exactly the same rules such as your Mac and Win OS when duplicate any files and folders
- it causes no technical conflicts within a FM solution since FM uses a hidden index instead of script name when assigning a script to a button