CAUSE
During upgrade process to PBAS 3.3.3-04.18 incorrect action was attached to event "Invoice has been paid".RESOLUTION
It is required to check an action attached to "Invoice has been paid" event on Top > Configuration Director > Event Manager > Events > Invoice has been paid > Actions > Invoice notification for customer screen and delete/disable it.
In the latest PBAS version this action is already disabled by default.
Keywords: not paid for the invoices, unpaid invoices, non-paid invoices, Invoice notification