CC reader working but requires frequent machine reset

[Pleb City]

Hi there,

I have an AP Studio 4 that I have installed an Ingenico card reader into, with MDB. The machine has an updated EEPROM.

After starting the machine, if I put it into service mode and out again, the card reader will work, payments are accepted and items vend.

After some time (could be hours or days), the card reader will stop working. It still says 'ready' and beeps when tapped with a card, but doesn't credit the machine.

If I then put it back into service mode, and out again, it will resume working.

Any ideas what could be wrong here?

Video:

https://photos.app.goo.gl/PwHhw5epfYmzoGy4A