This is a tip/improvement for whoever uses GRC as messaging system.
Due to inconsistencies SEFAZ faces on their systems from time to time, which generate return status codes that indicate that the batch is still being processed (105 and 106, for instance), GRC recurrently re-sends the batch request to SEFAZ. As a result, the number of attempts can surpass 1000, generating an overflow in some tables and making any further action impossible to be executed.
So, we have created the following SAP Note:
I strongly suggest you to apply this note as soon as possible in order to prevent this error from happening.