With this exotic helmet equipped and while the super is fully charged, orbs that are picked up charge the melee.
This is great, it is exactly what it is supposed to do.
But when the melee is fully charged, orbs are still picked and charge nothing. They are simply wasted.
As this is fundamentally different from the way orbs behave in the rest of the game, and there is no explanation for it in the helmet's exotic ability, I am confident that this is a bug.