Audiobooks vanishing from Books app on iPhone

On my SE after updating to 17.5 several of my audiobooks will NOT remain accessible in the Books app. They are .m4b files sent to the phone through iTunes.

I can put them on the device, but after refreshing the app most of them vanish.

They are uncorrupted on my computer, and I have done the following.

>Restarted the phone

>deleted them off the phone and put them back on multiple times

>recopied from storage drives

>deleted and reinstalled the Books app

>rebuilt the m4b files from source m4a files

I've even removed the books, deleted the booms app, done a hard restart, reinstalled the app, and put the books back on the phone, and several still vanish after refreshing the app.

(for some reason the selected device is not the correct one, it's a 3rd generation SE with iOs 17.5)