I didn't get the chance to speak with the devs in the last couple of days but i am certain that either this is the cause of a bug or they intended to remove the camouflage but for some reason it didn't get removed completely.
Let's wait for their answer to know which of them is it.
someone ingame, can't remember who, told me that Nightmare removed the invisible blip even after buying the camo (probably with the further intention to remove it) but this is all to confirm.
Anyways we should indeed either totally remove it, or at least meanwhile warn players that it won't work
About the DE, i wouldn't mind too much... btw it's a good item against teamers who gangbang players 5v1 or more