We are getting the an "Object reference not set to an instance of an object" error after we deployed a new version of a process. This affects process instances still on the old process. We've narrowed down the error to a specific datafield. When stepping through the datafields of a process instance, we are able to get the datafield by name, but the value and metadata returns a '(new System.Collections.Generic.Mscorlib_DictionaryDebugView<string,SourceCode.Workflow.Client.DataField>(pi.DataFields.m_Items)).Items[30].Value.Value' threw an exception of type 'System.NullReferenceException'.

The process is started though an IPC event.

Steps already taken:
-Redeployed the old process and migrated the processes to the redeployed version
-Migrated the processes to the new process
-The data injector tool cannot open the process (null reference exception)

It is possible make a copy of the process instance and update the Datafield, but the IPC event will need to be updated to point to the new ProcInstID
Is there a way to achieve this?