Mez + memblur
 

Not sure if this counts as a game mechanic or a spell issue:

When a mob is mezd, it shouldn't have the ability to aggro on someone.
IE mez a low level skeleton, then blur it. It immediately will spit out its
aggro message when you walk close to it (or when the blur lands, if you're too close).
On live I was able to mez a mob, blur it a few times, then invis and continue about my
day (with a /consider to make sure the blur stuck). Not sure if I can find proof of this
behavior, but I played an enchanter for 5-6 years if that helps :)

It works if you mez/calm/mem blur

memblur failure
 

At level 13, Memory Blur does not work for me. I have cast it 3-5 times on a mob and will still have it charge me when the root or mez wears off.

Azshara, 14 HE Enchanter

Are you out of aggro range when you cast it?
I usually test memblur by rooting the mob and then casting and seeing if the mob still turns to face me as I circle around it.