Yes it is. It seems to work off and on
I've seen this on my iPad Air 2 using an MFI certified Anker lightning cable and the official iPad 10W charger.
If I plug the cable into the charger then every so often I'll get a spate of Accessory Not Supported messages - unplugging and replugging the cable a few (sometimes many!) times seems to eventually fix this and allow it to charge.
If I use the exact same cable plugged into one of the USB ports on my MacBook Pro then it charges perfectly every time so it's almost as if it is the charger that it isn't recognising rather than the cable. It is all very odd.