The FATES for the books can't be in the normal rotation. They maybe are in their own rotation and flagged as rare ones so the spawn cycles are much longer. While waiting for one FATE in East shroud, I saw a FATE for the beast tribe there popping up for 20 times at least. On the 27 FATES I did for my Animus, there were maybe 1 or 2 FATES that spawned halfway normally. The vast majority of the rest were FATES I had no clue they even exist because they pop up so rarely. To me it seemed they used these FATES with sadistic intentions lol.