I was having the same problem. On closer inspection of the WP editor it appears that the Divi Builder is hiding the default editor as well as the AFC fields if the position is set to High (under title). Setting the AFC position to normal means the AFC fields now show under the Divi Builder.
Welcome to the Advanced Custom Fields community forum.
Browse through ideas, snippets of code, questions and answers between fellow ACF users
Clients need flexibility. Developers need a repeatable workflow that doesn’t have a steep learning curve. See how digital marketing agency Noiza found both with Advanced Custom Fields in our latest case study.https://t.co/BxQAy6COJt