Grapple Grenade used to begin recharging as soon as you used it, but due to an exploit with kickstart mods (which were completely gutted right after this change) where you could constantly recharge the grenade by just grappling to a tangle/grapple point, and also kind of "fly" into unintended places, Grapple was changed to no longer begin recharging in any capacity until you land on a solid surface. Well, soon after this nerf, "The Navigator" exotic and its catalyst released and allowed you to do the very same "exploit", without the restrictions of either: "be a Hunter with Widow's Silk" or "have a teammate with grapple too". Now, it has been 2+ years, and this Grapple nerf has still not been reverted, and I honestly don't see why. It wouldn't even be possible to exploit the old "infinite grenades" glitch in the same way, due to kickstart mods being hit with severe nerfs that cause them to require armor charge to function