The Bug
If you put a command-generated book on a lectern and click on a text section that has the change_page clickevent, even though the page appears to change, the redstone signal strength coming from the comparator does not update.
How to Reproduce
Create a book using the change_page clickevent via https://mcstacker.net/1.14.php or get a pre-made book by downloading this datapack. https://www.planetminecraft.com/mod/armor-stand-customizer-v2-0-1-14/ If you chose the latter option, you can get the book by typing /function cvt_armorstand:guide, placing an armor stand and dropping a book on it, or clicking on the tellraw after typing /reload.
Place the book on the lectern, open it, and then click the text with the change_page clickevent.
Notice how the page number and redstone signal strength doesn't match.
Thank you for your report!
However, this issue is a Duplicate of MC-142197.
If you have additional information, please add it to that report.
Please search before reporting, as it's likely that one exists already.
Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Customer Support – 📖 Game Wiki