I've noticed this as well, on live we would use "Tiny Cloak of the Darkest Night" in order to break charm. During swarm kiting on live this was used when the mob would be low health then we would break the charm then finish it off with dots.
Charm Kiting in general doesn't really work like live in Eqemu, I would be happy to demonstrate to any DEV who wishes to take on this challenge with my test bard on Raid Addicts.
King Mortenson
www.raidaddicts.org