... 4 days later. It's working now. I've done nothing but reboot - no more than I usually might.
I suspect I had somehow caused an issue with my scss files by disrupting Compass (?)
Dunno - whatever the case, all is better now.
@subhaze, Thanks I was just referring to the syntax highlighting I've been using. At the time I posted the issue I had done nothing to sublime or the plugin.
@lionhouse ... Goodluck!