Tested with file glob (approx 25 files) and everything works including using separator. 

In the last update, you refactored the block in question from a `return glob.find(cwd(src), options...` statement where the `Handlebars.SafeString` resided within to a `var html = grunt.file.expand(options.glob, cwd(src))...` statement where the SafeString is outside of this block.

The changes presented are not affected by the refactor and all appears to be working exactly how I expect. The only question I have is: Do you want to use the word `substance` for `content`? (Or any other word for that matter)
I used `zulu` when testing.