Supplier Invoice Date

SUGGESTED

Our AP is having instances where after an invoice has been saved in conflict, subsequent processing to change to authorised to pay and posting of the invoice is changing the supplier invoice date to the accounting date.  The due date, which is set from supplier invoice date is not changing so they are appearing on payment runs as they should in respect of their timing, but the artificially created Supplier Invoice Date makes it look as if they were not yet due.  Has anyone else experienced this?