HP have updated the firmware on printers that take these cartridges.
IMPORTANT PRODUCT INFO
There has been another firmware update issued for printers using HP 953XL and 903XL inkjets. Users are first asked to accept this update. If they do, current versions WILL NOT WORK.
These are the new firmware numbers that will not work:
Hp 953: 2006BR/A
Hp 903: 2006BR
Firmware versions can be checked in the printers menu in the settings
Disable automatic firmware updates.
Original HP cartridges will still work.