Problem is the low drop chance. If you are out of luck it takes so long to get one that you think something is wrong. After I got my Animus, it took me 2 weeks to get another ATMA at random with another char wearing a Zenith weapon. I also thought something is broken lol. But it wasn't. Just a quite low drop chance where you solely depend on luck. You can have 2 in 2 FATES, you can have none in 200 FATES.