Just ~2 days ago, we started encountering the error in the title in different scenarios. Moreover, when performing the scenario again after few minutes, the error doesn't occur anymore. In the picture below, the error occurred when opportunity stage is changed. Upon googling, migratedFromWorkflowRuleName is a flow metadata.
Since we have already migrated all our workflow rules to flow, we have no idea. What does the error mean? Most likely this affects flows that are from the migrate to flow tool.