Malformed ERR segments in ACK generated by HL7 EDI connector - mule

Question

I am working on a simple app that receives HL7 messages and returns an HL7 ACK. I started the implementation using the example found here: Acknowledgement example in HL7 DataWeave Examples section
When testing the example code, the ACKs are fine if there are no errors in the HL7, but when there are any errors in parsing the HL7 the ERR segments contain no fields:
MSH|^~\'|LABADT|MCM|ADT1|MCM|198808181126|SECURITY|ACK^A01^ACK|MSG00001-|P|2.6
MSA|AE|MSG00001-
ERR
Also the following warnings are found in the log:
WARN 2018-03-28 10:01:13,110 [[hl7ack].HTTP_Listener_Configuration.worker.01]
com.mulesoft.flatfile.1.3.0.lib.schema.hl7.HL7SchemaWriter: missing required value for component ERR-03: 'HL7 Error Code' for segment ERR at index 2
WARN 2018-03-28 10:01:13,110 [[hl7ack].HTTP_Listener_Configuration.worker.01]
com.mulesoft.flatfile.1.3.0.lib.schema.hl7.HL7SchemaWriter: missing required value for component ERR-04: 'Severity' for segment ERR at index 2
It seems like the schema of the ERR segment generated by the HL7 EDI transformer component does not match the default HL7 schema. Is there something that I am doing wrong? I tried including the ACK schema in the HL7 config, but had the same problem.
Below is Mule app code (same as example):
<?xml version="1.0" encoding="UTF-8"?>
<mule xmlns:tracking="http://www.mulesoft.org/schema/mule/ee/tracking"
xmlns:tcp="http://www.mulesoft.org/schema/mule/tcp"
xmlns:dw="http://www.mulesoft.org/schema/mule/ee/dw"
xmlns:http="http://www.mulesoft.org/schema/mule/http"
xmlns:hl7-edi="http://www.mulesoft.org/schema/mule/hl7-edi"
xmlns="http://www.mulesoft.org/schema/mule/core"
xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
xmlns:spring="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd
http://www.mulesoft.org/schema/mule/ee/dw http://www.mulesoft.org/schema/mule/ee/dw/current/dw.xsd http://www.mulesoft.org/schema/mule/tcp
http://www.mulesoft.org/schema/mule/tcp/current/mule-tcp.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-current.xsd
http://www.mulesoft.org/schema/mule/core
http://www.mulesoft.org/schema/mule/core/current/mule.xsd
http://www.mulesoft.org/schema/mule/hl7-edi
http://www.mulesoft.org/schema/mule/hl7-edi/current/mule-hl7-edi.xsd
http://www.mulesoft.org/schema/mule/http
http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd
http://www.mulesoft.org/schema/mule/ee/dw
http://www.mulesoft.org/schema/mule/ee/dw/current/dw.xsd
http://www.mulesoft.org/schema/mule/ee/tracking
http://www.mulesoft.org/schema/mule/ee/tracking/current/mule-tracking-ee.xsd">
<http:listener-config name="HTTP_Listener_Configuration" host="0.0.0.0" port="8080" doc:name="HTTP Listener Configuration"/>
<hl7-edi:config name="HL7_EDI__Configuration" identKeys="true" doc:name="HL7 EDI: Configuration">
<hl7-edi:schemas>
<hl7-edi:schema>hl7/v2_6/ADT_A01.esl</hl7-edi:schema>
</hl7-edi:schemas>
</hl7-edi:config>
<flow name="Acknowledgment">
<http:listener config-ref="HTTP_Listener_Configuration" path="/ack" allowedMethods="POST" doc:name="HTTP"/>
<hl7-edi:read config-ref="HL7_EDI__Configuration" doc:name="HL7 EDI"/>
<dw:transform-message doc:name="Transform Message">
<dw:set-payload><![CDATA[%dw 1.0
%output application/java
---
{
Name: "ACK",
MSH: payload.ACK.MSH,
Id: "ACK",
Data: {
ACK: payload.ACK
}
}]]></dw:set-payload>
</dw:transform-message>
<hl7-edi:write config-ref="HL7_EDI__Configuration" messageStructure="InMessage" doc:name="HL7 EDI"/>
<logger message="#[payload]" level="INFO" doc:name="Logger"/>
</flow>
</mule>

Answer 1

The ACK generated by the HL7 EDI component does not match the HL7 schema. Specifically the ERR structure does not contain the ERR-01 list. I used the following transform (in place of the simple transform above) to generate the correct acknowledgement.
%dw 1.0
%output application/java
---
{
Id: "ACK",
Name: "ACK",
MSH: payload.ACK.MSH,
Data: {
ACK: {
MSH: payload.ACK.MSH,
MSA: payload.ACK.MSA,
ERR: [{
ERR-01: (payload.ACK.ERR map ((eRR , indexOfERR) -> {
ERR-01-01: eRR.ERR-01-01,
ERR-01-02: eRR.ERR-01-02,
ERR-01-03: eRR.ERR-01-03,
ERR-01-04-01: eRR.ERR-01-04-01,
ERR-01-04-02: eRR.ERR-01-04-02,
ERR-01-04-03: eRR.ERR-01-04-03
}))
}]
}
}
}