Books app not playing certain audiobooks

My wife and I have Family Sharing, and she has been able to download a few of the audiobooks I purchased through the Books app to her iPhone XS Max running iOS 14.3. Book 1 will play fine, but Book 2 won't play on the iPhone. We followed the guides for removing and re-downloading the audiobooks, and restarting the phone, but that still didn't solve the issue. We tried some more trouble shooting, and when she AirPlays Book 2 to our AppleTV, it works just fine, but whenever she tries to just use the iPhone speakers for certain books, no audio is produced and the audio track doesn't move beyond 0:00 timestamp. We made sure the volume was turned up, and we tried using AirPods, but the issue continues for certain books. When I try to listen to Book 2 on my device, it works exactly as expected.

How can we get all audiobooks to play correctly on her device?