Ventura Books app can't find files

Launched Books for the first time on Ventura today…usually use the iPad…and every PDF file I’ve added gives me a ‘file cannot be found’ error on trying to open them. Books purchased from Apple open properly but any that were previously added as PDF files don’t open.

Has anybody else seen this and/or know the solution?

I have quite a few PDFs stored in Books (eg. cycling club newsletters going back 13 years). I’ve had no problem opening them in Ventura (or IOS 16,1 and iPad 16.1). However, I am a regular user of Books on my computers and hardly ever import from a mobile device.

Yep…it’s very strange.