Spells: Regeneration

[strider]

I think I can reproduce this bug reliably, but it appears that when a DOT spell/ability is starting to fade and you cast the spell Regeneration on yourself or that person, you'll get the Playername begins to regenerate message in the chat box, but the spell will not actually take hold. I've seen this happen 6 or 7 times with my shaman specifically.

Has anyone else encountered this or is this known?