Possible Bug interaction between Holds + Impassioned Serenade

[webdeath]

I started to notice on my Symphony Control Controller or Dominator if I use Impassioned Serenade, I see the Dot Damage as normal.  How ever if I use it on a Held target, say with Hymn of Dissonance or Chords of Despair, I will notice that Dot Damage will stop ticking even if I reapply Impassioned Serenade on the same enemy. 
I am not 100% Sure if this is a bug or not as I did see the Note stating that they will be inflicted with a Dot as long as they are confused.  So I'm not sure if maybe because they are being held, despite the power effecting them, they aren't technically confused since they are held? 
Also notice the same Note on Confounding Chant, and wonder if it also has the same problem? 

Figured I'd post this strange interaction here incase there is something buggy about that interaction.  

What I expected to happen:
Impassioned Serenade to continue to tick damage during a hold
What I witnessed happen:
Impassioned Serenade DoT damage stopped after it's original DoT duration ended on a held foe despite reapplication of Impassioned Serenade.