Registering AVRO schemas with error org.apache.avro.SchemaParseException: Can't redefine: com.example.items.ChildType

Schema Registry
1

I tried to register the following schema with maven plugin, but received org.apache.avro.SchemaParseException: Can’t redefine: com.example.items.ChildType error message.

The avro schema file content is

[{
  "type": "record",
  "namespace": "com.example.items",
  "name": "ChildType",
  "fields": [ { "name": "childList",
    "type": { "type": "array",
      "items": {
        "name": "Child",
        "type": "record",
        "fields": [
          {"name": "col1", "type": "string" },
          {"name": "col2", "type": "string" }
        ]
      }
    }
  }
  ]
},
{
   "type": "record",
   "namespace": "com.example.items",
   "name": "Parent",
   "fields": [
      { "name": "children", "type": "com.example.items.ChildType" }
   ]
}
]

The pom.xml contains (relevant part copied)

      <plugin>
        <groupId>io.confluent</groupId>
        <artifactId>kafka-schema-registry-maven-plugin</artifactId>
        <version>${confluent-avro.version}</version>
        <configuration>
          <schemaRegistryUrls>
            <param>http://localhost:8081</param>
          </schemaRegistryUrls>
          <subjects>
            <!--this tag prefix is the name of the topic-->
            <example.loader.t-value>src/main/avro/MultiTypeEvents.uavsc</example.loader.t-value>
            <test>src/main/avro/Parent.avsc</test>
          </subjects>
          <schemaTypes>
            <example.loader.t-value>AVRO</example.loader.t-value>
            <test>AVRO</test>
          </schemaTypes>
          <references>
            <example.loader.t-value>
              <reference>
                <name>com.example.items.ChildType</name>
                <subject>test</subject>
                <version>1</version>
              </reference>
              <reference>
                <name>com.example.items.Parent</name>
                <subject>test</subject>
                <version>1</version>
              </reference>
            </example.loader.t-value>
          </references>
        </configuration>
        <goals>
          <goal>register</goal>
        </goals>
      </plugin>

MultiTypeEvents.uavsc content is

[
  "com.example.items.ChildType",
  "com.example.items.Parent"
]

Could you help me how to successfully register such schema(s)?

Thank you in advance.