Looking at the names of the files you can see that they differ by an additional number. This is an indication that you copied such a file in place (for example using copy + paste). Try it out. Select one, say main.hbs press Ctrl+C and then Ctrl+V. You will get a new file named main 3.hbs (because main 2.hbs already exists.

So, I assume you have done this by accident before, when you believed the code editor has the focus, but instead the file tree was active.