After looking more into this I can say this is supposed to be a new unreleased weapon!
This shotgun has a cooldown bar, infinite ammo, and a pretty small damage for a shotgun (44) while i do like this gun please vault it and release when it is time. at least the devs now know what it is
Interesting. I was curious why the stats of some old weapon would change like that, but this makes some sense. Epic please, give us back Mythic version of Infiltrator Shotgun, which is my favourite shotgun in the game and now it is ruined because of this.
BTW: I would recommend change title of this thread because this one is telling absolutely nothing about this issue, so it is like invisible for someone who is going through all bug reports (and there is a lot of them).
When you have opened a page with your thread then you should have an icon of a pencil on the right side of the title (it is not too visible, so it can be easily overlooked). Click on it to change it.