Driver tells passenger with a physical e-ticket the payment machine isn't working.
Driver keeps the ticket.
Driver manually prints a receipt from a different terminal, which says fare was “received in cash”.
The payment process:
The driver keeps the e-ticket until another passenger takes a long distance trip. The passenger pays for the trip as normal, but the driver doesn't clear the meter. They then tap the e-ticket for that fare, which essentially gets paid twice.