Auto-straight in the Books app doesn't work

When I try to underline a sentence to make a straight Iine in the books app it doesn’t work anymore. I checked the settings of my apple pencil so many times and i found nothing wrong. I also tried to make a straight line in other apps (Goodnotes and notes app) and it actually worked. So it doesn't work in the books app only. If there's any suggestions to solve this problem, i will be so grateful. Anyway, I already sent a complaint straight to the apple team but up till now, i haven't gotten any reply.