I'm pretty sure this is an already known issue, but just in case I'll mention it since transcendece is out. Why am I doing this? Because I want a cool melee build for my Titan and Warlock using their respective strand melees. And the solution is not "spend all melee charges to activate it" because even when you are on your last melee charge and you use it, if you have the slightest amount of progress for the second charge the mod won't trigger. And this is not just for strand melees, use any warlock melee with claws of ahamkara and you'll see what I'm talking about. And this cannot be an intended thing because grenade kickstart works perfectly fine when you have multiple grenade charges.