Do you use Psalm of Warmth? A tank told me last week he hates when bards
use this, because it kills Ultravision, whether it be the spell or the
guise effect (he is a 50 warrior with a guise of the deceiver). I forgot
to check this, and he wasn't 100% sure which song it was. He simply said
"the song that puts up the wimpy damage shield that's a cold resist
buff" ;P. I've noted a large number of bards like to play this song for
the damage shield in the L30s range. Perhaps if you are doihng so, this
is the cause of your problem.

Ariell Thunderwolf, Karana