JPA AttributeConverter not honored in a Spring-data/hibernate query when used in a composite key

You can't use Convert and Id annotations on same field, nor Convert and Enumerated. Use EmbeddedId instead as seen by @Converter documentation:

Note that Id attributes, version attributes, relationship attributes, and attributes explicitly annotated as Enumerated or Temporal (or designated as such via XML) will not be converted.

See: https://docs.oracle.com/javaee/7/api/javax/persistence/Converter.html, JSR-338, Chapter 11.1.10 Convert annotation, page 438.