The "Cancel" addon appears to only be working sometimes - this just started happening, I believe, since the most recent update (I noticed it on 10/25/2015 and on 10/23/2015 it was working fine).
It'll work for 1 buff, but then break and not work for other buffs... As an example: I load the addon, get Copy Image (4+), use //cancel Copy Image (4+), and Copy Image (4+) is canceled. I then get Copy Image (3), and //cancel Copy Image (3) fails to work (I tried //cancel Sneak and other buffs as well, but no luck), but it will still work on Copy Image (4+).
Just to add to this - BlinkMeNot is still changing my race/gender whenever it's used. Not sure if this is working as intended or broken as well?