R053951 Not Running During Final Update

During our last payroll processing cycle, we had numerous (32 out of 93) Final Updates (R07250) that did not run the R053951 UBE, thus payroll journal entries were not created in the General Ledger.  The problem payrolls were not all together;  we had three not run R053951, then one that did, then ten that did not, followed by one that did, then another five that didn't, etc.  We have never experienced something like this before.  Nothing has changed as far as system set up/configuration.  No new payroll IDs were created.  Anyone have any ideas?