No idea about the warranty, but would guess it should be covered, assuming it's the cable at fault. The only real reason a cable could fail like this, from a cable-related fault, is is the crimped connection between the cable and the pin was faulty.
There's a possibility that the cable may have been fine, but that it was used with a charge point that had a failing socket. Charge point sockets that have reduced spring pressure to grip the pin in the connector are a known failure mode, so it's worth checking any that you use regularly for signs of damage.
Also, as I mentioned in this thread:
Get your charge cables regularly inspected and tested! it's well worth getting cables checked regularly. An end-to-end conductor resistance check would probably pick up early signs of a failing crimped connection, from the increased resistance. Not much help for a nearly new cable, though.
Cables can be fixed fairly easily, as long as spare pins are available. The lead supplied with the car has no spare pins, though, as it's a 3 phase one, but anyone with a single phase cable will have two spare pins, as the L2 and L3 pins won't be connected to anything, so can be swapped over with a damaged pin. Unfortunately you cannot easily swap pins on a 3 phase cable, as they are crimped after they are inserted in the inner housing. Fitting the new pin requires a hydraulic crimp tool, with the right size mandrels.
