Basically, I'm going to use Linguist as an example, but the same thing occurs with Atom. I'm just too lazy to take screenshots. :)

Take a look at:

• Syntax highlighting randomly turned off.
• It's kind of on again.
• Now it's back.
• Lost it again.
• Black docstring.
• Only the docstring end was detected here, so it completely screws up highlighting for the entire rest of the file.

All of these issues are from one file. Now, as I said, these all also occur in Atom, which makes editing Python files...fun. :/