I have a site where the Learndash quizzes won’t submit, giving an error that all questions must be answered even when they are all answered. I went through the process of deactivating and re-activating every plugin in the site, and then tested the default theme. I made sure everything was updated as well. Submitting the quizzes works with all the plugins activated and with a default 2024 theme, but not with PRO activated, showing there’s a conflict there.
I have the site set up on a staging server so you can get in and see for yourself. I’ll be happy to give you access and relevant links in a private note.