@Maxvax: I'm sorry to hear that you have encountered this issue. As a workaround, try removing the existing thumbnails, then head to the Google Play Books app, select the relevant books, and re-add the shortcuts from here. If the issue persists then please send us an Error Report with accompanying System Log Data, and we will be able to look into this in further detail. To do this, please head to the Members app > Get Help > Error Report > Tap 'OK' to send System Log Data > Select the symptom, and include as much detail as possible. To ensure your logs accurately reflect the issue you're experiencing, we'd like you to submit your report within 5 minutes of encountering the problem. Our engineers will then investigate this and respond to you with a solution via the Members app.