I just picked this spell up yesterday and have only really tested it in Icewell Keep, so it's also possible that this is an issue with the mobs there rather than the spell itself.
Also note that it's not swarm kiting that I'm trying (not comfortable enough to try that yet!), rather charming a pet and sending it on a single mob.
What I've noticed so far is that the charmed pet doesn't seem to generate any threat at all. I have tried charming the pet and sending it against a mob without casting anything at all on the mob in question, and the mob will chase me indefinitely until it dies (all damage being done by the pet, no debuffs cast or even buffs on myself or the pet - looping charm song the entire time).
As a bard with gear I've found questing while leveling up, I find it very difficult to solo by 'traditional' means and have resorted to some semblance of charm kiting. I was just wondering: is this an intentional thing to try to prevent charm kiting?
I also tried this with lower songs while I was leveling up (Solon's Song of the Sirens I think) and I was able to send the pet on a mob and let them beat each other up, grab a new pet, rinse, repeat, etc. However, with either this new spell or the particular mobs in Icewell, this seems to be impossible.
Is this a bug/known issue or something intentional? I would appreciate any feedback I can get on this. I have noticed that there aren't very many main/solo bards on this server

Thanks!
****EDIT****
After some further testing, this is an issue in Icewell Keep (at least on the mobs I tried). The spell works fine in other zones.
Thanks again
