importMappings not working I can not replace import

      <version>2.3.1</version>
      <executions>
        <execution>
          <id>generate-server-jar</id>
          <phase>generate-sources</phase>
          <goals>
            <goal>generate</goal>
          </goals>
          <configuration>
            <inputSpec>${swagger-gen.yml}</inputSpec>
            <language>spring</language>
            <configOptions>
              <sourceFolder>src/gen/java</sourceFolder>
              <apiPackage>${swagger-gen.api.package}</apiPackage>
              <modelPackage>${swagger-gen.model.package}</modelPackage>
              <serializableModel>true</serializableModel>
              <useJaxbAnnotations>false</useJaxbAnnotations>
              <dateLibrary>java8-localdatetime</dateLibrary>
              <generateApiTests>false</generateApiTests>
              <generateModelTests>false</generateModelTests>
            </configOptions>
            <typeMappings>
              <typeMapping>OffsetDateTime=LocalDateTime</typeMapping>
            </typeMappings>
            <importMappings>
              <importMapping>java.time.OffsetDateTime=java.time.LocalDateTime</importMapping>
            </importMappings>

          </configuration>

Start with the shown Spring generator configuration and trace how typeMappings and importMappings are handled during generation. Reproduce the configuration with OffsetDateTime mapped to LocalDateTime, then verify that generated Java files import and use LocalDateTime instead of OffsetDateTime.