The new Marksmanship 2-target cleave talent, Aspect of the Hydra, currently doesn’t work in one of the only situations in the new raid where it would be optimal. The bosses are more than close enough for other classes’ cleave during the clash, but somehow this talent doesn’t match that.
Considering that Multi-Shot doesn’t reach both bosses either, MM has no way to cleave during the clash at all except for Explosive Shot and Lunar Storm from Sentinel (or maybe with Volley, but I’d be shocked if Trick Shots cleaves properly given this issue). Multi-Shot’s tooltip also says “hitting your current target and all enemies within 0 yards” too, so it seems these just need another bug testing pass between text and functionals.