There have a gif that can descript this issue:

What version are you using? Is the book written to support localization?

I am using the latest version(1.12-2.1.7-62),the book supported localization,but the text would change after restarted the game.

That is not the latest version. Nevermind, I thought I had upped the MC version to 1.12.2.

Either way, this was fixed in a87e69c

The only other way for this to happen would be if the book was passing localized text to the pages.

About this guide book (code):https://github.com/TeamLapen/Vampirism/blob/1.12/src/main/java/de/teamlapen/vampirism/items/ItemVampireBook.java
The case also happened on cyclic mod,but I think it used the lang text:
https://github.com/PrinceOfAmber/Cyclic/blob/master/src/main/java/com/lothrazar/cyclicmagic/guide/GuideRegistry.java