A matching gets automatically removed if:
A Bill is voided/deleted/rejected (the status becomes Cancelled OR the status becomes Rejected)
A Purchase Order is cancelled/deleted (the status becomes Cancelled)
The Supplier is not the same anymore
The Currency is not the same anymore
The date has been changed (matching to a retrospective Purchase Order is not enabled)
* The Bill should be issued on the same day as the Purchase Order, or later.