Issue with syncing books to iPhone

Is anyone one else having an issue with Books on the latest beta of Catalina? I am currently on Beta 4, and when I plug in my mobile devices (I have an iPhone 7, iPhone 8, iPhone 6, and and old iPhone 4) when I go to the audibooks section in finder when trying to sync any audiobooks, that whole section is empty. I open up Books on the machine(s) (this is happening on both machines I have at home, a 5K iMac and a 2014 Macbook Pro) and can see the books ok and they play fine on the desktop/laptop. I even went so far as to take a backup, delete all the books and reimport them into books seeing if that would help, but it did not work. This strategy actually DID work on Beta 3 when I ran into the same issue. What is weird is I have Beta 4 on a machine at work, and on that one, everything is fine, I can see the books and sync from that machine to my iPhones.