MDSERR310029|The status of the specified batch is not valid.
This error occurs when using the entity-based staging process (leaf tables). If multiple entries of the same BatchTag value are executed concurrently, this error can appear. It can happen in the same entity or different entities or models.
The best solution I’ve found is to update mdm.tblStgBatch and set the status_id for the BatchTag to completed. You can then update the BatchTag name in the leaf and reset the ImportStatus_ID back to 0 and reprocess the batch.
An alternative is to append a timestamp to the BatchTag to make it unique. That should keep this from happening.
Credit on this to James Serra, who has a good post on this error, and to Microsoft.