Hello!
I do not know if this is operating as intended, but I cannot seem to measure any effect on target enemy's endurance recovery, or endurance under the effect of Poison's Poison Trap. I have tested it against players in PVP and enemy mobs, and I just cannot measure any effect other then the minor damage, and occasional holds. Unless the effect is something that does not show in Power Analyzer, this power just seems mostly useless as it is.