I am using Lexik Workflow Bundle to manage workflows. I have created a simple workflow in video_derivative_workflow.yml and put the following into my admin class:
/**
 * @return string
 */
public function getWorkflowName()
{
    return 'video_derivative_workflow';
}
... and I now find that I'm getting the following fatal error:
Call to a member function getStepName() on null
Anyone know what this means in the context of this bundle?
