Inconsistent behavior with including other grammars

[irrationalistic]

I'm working on the https://github.com/irrationalistic/atom-tasks package and I'm experiencing some odd inconsistency with including source.gfm in my grammar. I'm not sure if this is the right place to ask this, but thought I'd try.

Essentially, one part of my own grammar sources content from the gfm language. https://github.com/irrationalistic/atom-tasks/blob/master/lib/tasks.cson#L44.
This grammar file is actually loaded in manually and added to the listing since I need to make a textual regex change into the grammar itself before attaching it. Sometimes it will show, sometimes not. A fresh install of the tasks package works, but restarting the editor can cause it to go away.

I have it symlinked from a different directory, but it seems to no longer bother to even run the gfm highlighter on my tasks files! It has, even today, done it, just, sometimes...

Sorry this is really vague but I'm not sure where to go next! Any help is appreciated.