The reason why it's applied before your spell is because you might cast crowd-control spells (Flash Freeze, Nightfall), which would be immediately broken by the icicle, if it happened after. This would arguably be even worse, because usually there's a very good reason when you want to take a particular mob out of combat for a while.
What I can do, however, is mark Spiritual Regeneration as a spell that doesn't cause spirit bottles to proc.
