When are records in the WMPRTXREF table deleted


I have an issue regarding the removal of records in the WMPRTXREF table. The problem occur when I want to resubmit a failed process model. The reply that I get back is not correlated back to the original model. This would not happen if the correlation record was still in the WMPRTXREF table. I’m trying to figure out when these records are deleted and if this can be avoided in some way.
My guess is that this is done by some scheduled service, that cleans up any records to either failed of completed models.