The json commands is not working properly. This command is giving the player wrong text in a book:
/give @p written_book 1 0 {pages:["[\"\",{\"text\":\"I'm green\",\"color\":\"green\",\"bold\":true},{\"text\":\"I shld not\",\"color\":\"none\",\"bold\":false}]"],title:Test,author:Viloz}
If you look in the command, the "I'm green" part is green and "I shld not" is not green, but ingame "I shld not" is green anyways.
Does MC-62866 describe your issue?