Help, I was dispelled!Follow

I have always been under the impression that cancel magic spells worked by dispelling effects from the top down on the buff window. I have always carefully placed junk buffs (like grim aura, see invis, etc) in slots 1 and 2 to prevent getting important buffs dispelled...

So I am farming a bit of velium in Crystal Caverns and happen upon a Ry'gorr Oracle. He starts casting his cancel magic spell and I watch my buff list.. BOOM! buff slot 11 vanishes. Buff slot 11 was KEI .

I know cancel magic is unresistable, but at his level he could only strip 1 effect (or effect counter?). So I ask, was this just a coincidence? Did my KEI just happen to expire right then or am I completely off on how buffs are dispelled? How does cancel magic really work?

Thanks for clarifying that, and yes, I'd like to take a look at the detailed description if you have it around!