Sorry cant help on the first bit then. I've never been able to get a regen while fighting an EP mob. Ever. But that's just me.

As to the hate issue i have seen that plenty, but i've just always attributed that to server lag. Kinda like how on many occasions since enhancing magic buffs have been added, Klaxon will be almost done reapplying Haste to me or someone else before i even get the chatlog notification that it has worn.