Has anyone ever seen an issue where vRO is trying to run two instances of the same workflow at the same time. One runs and one fails. The one that fails the error is "The operation is not allowed in the current state".
Example is two different uses submit a BluePrint to run at the exact same time. One will complete and one will fail.
If the workflow is run 100 times but never close together in time, they will always complete OK.