[BUG] Inheritance and Maps canno coexist

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?

Description

The attached file represents an inheritance containing, in the subclass, a hashmap with a custom type. Well, I don't get this, but I get different results.
As a result I'd expect to get

public class SubObjectDTO extends SuperObjectDTO {
private Map<String, MapElementDTO> additionalMap;
....[getters and setter and whatever more]---
}
public class SuperObjectDTO {
private UUID id;
private String superProperty1;
private String superProperty2;
....[getters and setter and whatever more]---
}

public class MapElementDTO {
private int property1;
private boolean property2;
private String property3;
....[getters and setter and whatever more]---
}

while I get the Super class and the map element ok, the subclass varies depending from the inclusion of the clause of allOf. If I add this, I see the element with the properties of the superclass, but no additionalProperties. If i remove this, I dont get the super class props but just the additional ones.
Is this a bug or I'm doing a mistake?

openapi-generator version

openapi-generator version
4.2.2

OpenAPI declaration file content or url

See attached gist
https://gist.github.com/maxper75/62a7cdac09037679641c56f552bc21ef#file-buggy-openapi-inheritance-map-json

Command line used for generation

openapi-generator generate -g spring -i model.json -o prova

Steps to reproduce

just launch the command :D

Start with the OpenAPI declaration in the linked gist and run the reported spring generator command with openapi-generator 4.2.2. Inspect the generated SubObjectDTO, SuperObjectDTO, and MapElementDTO classes with and without the allOf clause. Done means the subclass preserves inheritance and includes the typed map alongside the superclass properties.