After migrating from 8.3.2 to 9.1.0, if we have any workflows/custom workflows used from 8.3.2 ( For example: wfin26productaddinternaleditv1) that has CreateWorkItem action in the workflow throws Null Pointer Exception at create workitem action.

com.tibco.mdm.ui.workflow.engine.workitem.templates.DQMatcherWorkItem. The resolution is changing the below properties in configValues and workflow.

<ConfValue description="The document type templates that are used for matcher work item." isHidden="true" isHotDeployable="true" name="DQ workitem templates used" propname="com.tibco.cim.dq.template.matcherworkitem" sinceVersion="8.2" visibility="Advanced">
<ConfList>
<ConfListString value="com.tibco.mdm.ui.workflow.engine.workitem.templates.MatcherWorkItem"/>
</ConfList>
</ConfValue>

To:

<ConfValue description="The document type templates that are used for matcher work item." isHidden="true" isHotDeployable="true" name="DQ workitem templates used" propname="com.tibco.cim.dq.template.matcherworkitem" sinceVersion="8.2" visibility="Advanced">
<ConfList>
<ConfListString value="com.tibco.mdm.ui.workflow.engine.workitem.templates.DQMatcherWorkItem"/>
</ConfList>
</ConfValue>
 

And workflow files needs to be changed the references from com.tibco.mdm.ui.workflow.engine.workitem.templates.MatcherWorkItem to com.tibco.mdm.ui.workflow.engine.workitem.templates.DQMatcherWorkItem