This is an issue that was previously resolved!
If you change of pages of a writable book that you aldready wrote into it, especially going back to previous written pages, the game will crash with: The game crashed whilst rendering screen
Error: java.lang.StringIndexOutOfBoundsException: String index out of range: 235.
Linked issues
Comments 3

I don't understand you. I wouldn't have made the post if the bug wasn't active in the newer snapshots... I don't understand why you marked this as a duplicate, you're brushing the issue under the rug. It's back.
You reported a bug for 20w17a, while it was already fixed in 20w18a. See linked ticket.
As you said it's already fixed.
Please don't create reports about issues that have been fixed.