Incorrect DDL with Postgres, @MappedSuperclass, Generics and UserType

Description

This problem is similar to HHH-15970, but still exists with Hibernate 6.1.7.

It occurs when you have a generic @MappedSuperclass with an enum field that is mapped via a custom UserType. The databse field is generated as a bytea, where an integer type is expected. When saving an object, there is of course a type conflict.

Please have a look at the attached test case. With Hibernate 6.1.7 and Postgres it fails as follows:

Caused by: org.postgresql.util.PSQLException: ERROR: column "myenum" is of type bytea but expression is of type integer
  Hint: You will need to rewrite or cast the expression.
  Position: 93
	at app//org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2676)
	at app//org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:2366)
	at app//org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:356)
	at app//org.postgresql.jdbc.PgStatement.executeInternal(PgStatement.java:496)
	at app//org.postgresql.jdbc.PgStatement.execute(PgStatement.java:413)
	at app//org.postgresql.jdbc.PgPreparedStatement.executeWithFlags(PgPreparedStatement.java:190)
	at app//org.postgresql.jdbc.PgPreparedStatement.executeUpdate(PgPreparedStatement.java:152)
	at app//org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:197)

With Hibernate 6.2, however, it is successful. I couldn't find a suitable JIRA issue for it though.

I would like to ask for a fix for 6.1. Because we are currently limited to JakartaEE 9.1, the use of Hibernate 6.2 is unfortunately not yet an option for us.