I experimented with your test case, which uses Hibernate 6.6.2.Final, I haven’t found any issues after adding the @Embeddable to the Address class.
After more internet searching, I found this Mapping a collection of embeddable with a JSON type.
I tried upgrading the Hibernate version in my spring boot app to 6.6.2.Final. Now everything worked as expected.
For the moment, I reverted the changes because Spring Boot 3.4.0 (which includes Spring Data JPA 3.4.0 and Hibernate 6.6.2.Final) will be released tomorrow. I’ll just wait and upgrade my project to solve it.