BPMN2 process causes Stunner to crash with EMF Error

When trying to open this process definitions:
https://github.com/DuncanDoyle/rhpam7-client-onboarding-enrichment-repo/blob/emf-error/src/main/resources/com/myteam/client_onboarding_enrichment/EnrichmentProcess.bpmn

with the new designer, the designer seems to crash and the workbench shows the EMF Error as can be seen in the attached screenshot.

Note that this process has been completely designer with new editor. I suspect that it happened when I renamed a process variable (requiredDocuments) that was used as the input collection for my Multi-Instance sub-process, and I forgot to reconfigure that element with the new name of the collection.

The only way to resolve this was to clone the repo, checkout the previous commit of my EnrichmentProcess.bpmn file and push it back to the workbench.