Some printers have "Cartridge is low" settings where they will stop printing when the supplies end up in "Very Low" message and the data collector do not get a valid reading back from the supplies.

By default most printers will stop when the cartridge reaches the "Very Low" threshold.

If it is set to "Stop" or "Prompt to continue" you could consider to change it to "Continue".

This could help get a valid reading back from the supplies when they are "Very Low" and also ensure that the customer empty all the supplies and do not take them out before they are empty.

Maybe also lastest printer firmware could help on a issue like this.