Hi @Retired_mod , the problem looks somehow related to clusters. This is what I have done:

1. deploy the workflow using dbx
2. try to run: it fails with the above error
3. manually change the cluster definition (e.g., change the runtime)
4. try to run: it works
5. manually undo the change and try to run: it still works

I have compared the JSON definition of the workflow before and after the manual changes and it looks identical. Any suggestion?