PRC: Generate Cost Accounting Events is missing (not processing) pending costs.

Rerunning the generate cost accounting events does not resolve the problem. But if I submit PRC: Generate Cost Accounting events with a Process Category such as Labor Costs included, pending transactions are picked up again and everything is fine for a week or two. It seems like there is a buffer issue and the same cursor results get used until a parameter is changed. Is this the problem? What can be done to stop this from happening? There are a number of other programs and reports that we are having similar issues when scheduled through the concurrent manager. Executing the