MEL selection mask reference.

Sometimes the simplest things can be the most frustrating, especially when they don't work the way you expect them to.

In this case, some selection masking in MEL wasn't doing what it was supposed to be doing (returning a previous selection in face mode) which was causing lots of frustration and beard scratching.

That is until Christopher Crouze's post on Proper Selection Masks for Maya popped up on google search. Thanks Chris!