[JAVA] Bug generating classes using JsonProperty Annotation

Description

I have used the swagger-codegen-maven-plugin to generate model classes from a yaml file.
In this yaml there are a couple of properties that are not camelCase but lowercase with hyphens:

responseElements:

type: object

properties:

x-amz-request-id:

type: string

x-amz-id-2:

type: string

The generated classes get the JsonProperty annotation using these properties, so far so good.

When I create a class and use the proper setters and getters to fill the fields something strange happens, the json from this object contains both the fieldnames and the JsonProperties:

        "responseElements": {
            "xamzRequestId": "xAmzRequestId",
            "xamzId2": "xAmzId2",
            "x-amz-request-id": "xAmzRequestId",
            "x-amz-id-2": "xAmzId2"
        },

How do I get rid of the first 2 elements? They are IMO faulty and I cannot use them in my application.

Swagger-codegen version

3.0.41

Swagger declaration file content or url

responseElements:
  
  type: object
  
  properties:
    
    x-amz-request-id:
      
      type: string
    
    x-amz-id-2:
      
      type: string

Start with the swagger-codegen-maven-plugin Java model-generation path and reproduce the issue using the YAML declaration shown in the report. Inspect the generated model's accessors and JsonProperty annotations, then verify serialization; done means the output contains only the hyphenated property names rather than duplicate Java-derived names.