Compass Listener error

I started using Compass and it's really weird. When I use the command watch

, it detects the changes and overwrites the main CSS file as expected, but it randomly returns an error for some partial files and doesn't compile them into the main CSS file.

For example: When I change _fonts.scss it works fine. when i change _intro.scss the terminal gives me the following error:

modified sass/pages/_intro.scss 
[Listen warning]: Change block raise an exception: undefined method `to_tree' for nil:NilClass

      

        
        
        
      

    

This is just a random error, it can happen to any file and the only thing that solved it was to press Cmd + C and use the clock again.

Files that were once compiled can now return this listener error and vice versa.

Why? and how can i fix this? It really slows down development to hit Cmd + C and run watch every 10 minutes or so.