Possible Stack Issue: Chaotic Power & Blessing of Devotion

[Nerva]

The spell Blessing of Devotion seems to conflict with the Chaotic Power buff from Call for Blood's recourse effect.

Blessing of Devotion is a Sune buff, that provides 10% spell haste and lasts 40 minutes. Chaotic Power is a short-duration (1 minute, song window) buff that provides +100% spell power to DoT spells.

These spells are about as different in effect as you can get; the only similarity is that they both affect spells. Is there a particular reason why these two buffs cancel each other out?