I've noticed something similar on my /dark Dominator. It seems to be an issue with the alt animation paired with quicksnipe. Activating Moon Beam with the alt animation somehow sets many of my other attack animations to their "alt" variants, despite the fact that I didn't select those variants for those powers. Also, when I'm experiencing the bug with those attacks, sometimes flying (with Mystic Flight, but I imagine it would be true of other methods of flight too) keeps looping the beginning of /em flypose1, the transition from normal flying to the flypose. The animation errors persist for awhile after I use the snipe, but I couldn't say exactly how long.