In one of the recent updates a month end cut off was introduced, but it is not actually a month end cut off.
It still allows for an invoice to be exported with an invoice date into a period that has been completed & cut off.
I.E December Invoice
Received in January - Input in January - Exported in January
Month end cut off should allow for that invoice to be posted with it's correct date of December, but on export to Sage put it within the January period as December has been cut off.