Flowable Modeler CMMN Importer issue

We use Flowable Modeler to build and support CMMN project. We are having an issue where a case model created and exported with Modeler, then imported with the same Modeler application, is missing all extensionElements.
This is the exported file of the case after it has been configured:

<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://www.omg.org/spec/CMMN/20151109/MODEL" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:flowable="http://flowable.org/cmmn" xmlns:cmmndi="http://www.omg.org/spec/CMMN/20151109/CMMNDI" xmlns:dc="http://www.omg.org/spec/CMMN/20151109/DC" xmlns:di="http://www.omg.org/spec/CMMN/20151109/DI" targetNamespace="http://www.flowable.org/casedef" exporter="Flowable Open Source Modeler" exporterVersion="6.7.2">
  <case id="authorization" name="Authorization" flowable:initiatorVariableName="initiator">
    <documentation>Authorization Case</documentation>
    <extensionElements>
      <flowable:channelType xmlns:flowable="http://flowable.org/cmmn"><![CDATA[kafka]]></flowable:channelType>
      <flowable:eventType xmlns:flowable="http://flowable.org/cmmn"><![CDATA[com.cnc.ph.um.intake.multichannel.auth.created]]></flowable:eventType>
      <flowable:startEventCorrelationConfiguration xmlns:flowable="http://flowable.org/cmmn"><![CDATA[storeAsUniqueReferenceId]]></flowable:startEventCorrelationConfiguration>
    </extensionElements>
    <casePlanModel id="casePlanModel" name="Authorization" flowable:formFieldValidation="true" autoComplete="true">
      <planItem id="planItem1" name="Process Create Auth Event" definitionRef="sid-3B8FA4F3-A0A9-442A-97FB-B1CB3B00BD9D"></planItem>
      <task id="sid-3B8FA4F3-A0A9-442A-97FB-B1CB3B00BD9D" name="Process Create Auth Event" isBlocking="false" flowable:type="script" flowable:scriptFormat="javascript">
        <documentation>Script to process the information received with the event that created the case.</documentation>
        <extensionElements>
          <flowable:field name="script">
            <flowable:string><![CDATA[const a = '';]]></flowable:string>
          </flowable:field>
        </extensionElements>
      </task>
    </casePlanModel>
  </case>
  <cmmndi:CMMNDI>
    <cmmndi:CMMNDiagram id="CMMNDiagram_authorization">
      <cmmndi:CMMNShape id="CMMNShape_casePlanModel" cmmnElementRef="casePlanModel">
        <dc:Bounds height="714.0" width="718.0" x="195.0" y="45.0"></dc:Bounds>
        <cmmndi:CMMNLabel></cmmndi:CMMNLabel>
      </cmmndi:CMMNShape>
      <cmmndi:CMMNShape id="CMMNShape_planItem1" cmmnElementRef="planItem1">
        <dc:Bounds height="80.0" width="100.0" x="330.0" y="180.0"></dc:Bounds>
        <cmmndi:CMMNLabel></cmmndi:CMMNLabel>
      </cmmndi:CMMNShape>
    </cmmndi:CMMNDiagram>
  </cmmndi:CMMNDI>
</definitions>

And this is the export after the case has been deleted, imported back and re exported:

<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://www.omg.org/spec/CMMN/20151109/MODEL" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:flowable="http://flowable.org/cmmn" xmlns:cmmndi="http://www.omg.org/spec/CMMN/20151109/CMMNDI" xmlns:dc="http://www.omg.org/spec/CMMN/20151109/DC" xmlns:di="http://www.omg.org/spec/CMMN/20151109/DI" targetNamespace="http://www.flowable.org/casedef" exporter="Flowable Open Source Modeler" exporterVersion="6.7.2">
  <case id="authorization" name="Authorization" flowable:initiatorVariableName="initiator">
    <documentation>Authorization Case</documentation>
    <casePlanModel id="casePlanModel" name="Authorization" flowable:formFieldValidation="true" autoComplete="true">
      <planItem id="planItem1" name="Process Create Auth Event" definitionRef="sid-3B8FA4F3-A0A9-442A-97FB-B1CB3B00BD9D"></planItem>
      <task id="sid-3B8FA4F3-A0A9-442A-97FB-B1CB3B00BD9D" name="Process Create Auth Event" isBlocking="false" flowable:type="script" flowable:scriptFormat="javascript">
        <documentation>Script to process the information received with the event that created the case.</documentation>
      </task>
    </casePlanModel>
  </case>
  <cmmndi:CMMNDI>
    <cmmndi:CMMNDiagram id="CMMNDiagram_authorization">
      <cmmndi:CMMNShape id="CMMNShape_casePlanModel" cmmnElementRef="casePlanModel">
        <dc:Bounds height="714.0" width="718.0" x="195.0" y="45.0"></dc:Bounds>
        <cmmndi:CMMNLabel></cmmndi:CMMNLabel>
      </cmmndi:CMMNShape>
      <cmmndi:CMMNShape id="CMMNShape_planItem1" cmmnElementRef="planItem1">
        <dc:Bounds height="80.0" width="100.0" x="330.0" y="180.0"></dc:Bounds>
        <cmmndi:CMMNLabel></cmmndi:CMMNLabel>
      </cmmndi:CMMNShape>
    </cmmndi:CMMNDiagram>
  </cmmndi:CMMNDI>
</definitions>

We are seeing this issue with both running Flowable in Docker and with Tomcat and Postgresql.

I would appreciate any help that will get us on the right path of addressing this problem!