I am also seeing this with 6.2.0.Final (via Quarkus 3.0.2.Final et al). In my case I have subclasses using custom user types to SerDe via Jackson from postgres jsonb columns. Otherwise the symptoms are the same.

In debugging I discovered what I believe to be the source of where it all goes wrong. When an EntityPersister is being constructed (via AbstractEntityPersister#initOrdinaryPropertyPaths(...) there are multiple entries for the same column name in the subclassProperty*Closure(s). This is fine except that AbstractPropertyMapping#addPropertyPath(...) drops duplicate registrations when the types are not association types, thus the first discovered subclass’s mapping is chosen.

Hope that helps!