It happens to all the weapons and armor from expansion 2, it happens because even though you don't see the attack/armor upgrade the game thinks that It's there. For example: The Ram exotic helmet has only 3 perks shown but it also has 42 light level straight away, the game thinks that you still have to upgrade the increase armor perks so that's why it shows you that it upgraded but when you check, there is no upgrade to be made. Hope i helped, and if you can, spread this post if someone is confused about it. :)