Dispatched POs later found with budget status: Not Chk'd.

We are having several campuses reporting that POs that had been approved, budget checked, and dispatched are being later found with a budget status of Not Chk'd.  The problem is discovered when AP tries to create a voucher for an invoice and cannot due to the budget status of the PO.  More peculiar is that only the Budget Header Status is Not Chk'd.  The Budget Line Status remains as Valid (or Warning) for each line.  Purchasing is able to manually budget check the POs again to resolve the issue, but this is after the fact.

This is happening for POs in which a Change Order has been created and for POs where no Change Order is shown.  I know that there is a known issue where Change Orders are not being created as they should be and that may be affecting some POs.  I have also seen an issue where PO Dispatch is causing the budget status to change to Not Chk'd, but that also reported PO Status changing to Approved.  These POs are being found as Dispatched/Not Chk'd.