I was using the Void Gauntlet, and I notice this often when grinding large packs is that sometimes the gauntlet will bug out and the void blade animation will be present around the Floating Ring thing, and the left click will be the stock ranged Void Gauntlet attack. The Void Blade skill goes on cooldown and have to wait to respawn it.
This can be problematic since the Melee Void Blade is a large part of the tree.