...or it was a defective warhead. Has happened a number of times in the past.
The way the damage appears to me, and based on what I can see of the possible angles, known parameters of the CIWS, and the fact that there were two missiles flying, it looks to me like the boys on that frigate, did their job. They were most likely maneuvering, to keep one or more of the missiles, just inside the enagement envelope.
I don't see a major hull penetration, just blast effects, which explains why it's still on an even keel, they didn't get holed, or didn't take a big hole at or below the waterline. Perhaps just shrapnel penetrations.
If the CIWS engaged, and detonated the missile at close range, it would account for the burned areas on deck, the crewmen blown overboard and still missing, and the fires. Hot shrapnel in an area where you have fuel lines for the engines and embarked Helo, would cause some very hot, quick spreading fires, in the very guts of the ship.
Fire suppression systems would quickly knock down the worst of the flames, but until you can ventilate, enter, and recover compartments and equipment, the ship is basically dead. Not much room for redundant systems on a ship this size.
No mention of any countermeasures being deployed, but with only about 60 seconds to deploy them, until impact, the srboc and ECM gear, were useless that close in to shore, and the missile was already in terminal homing when the blooms went out.
This old sailors opinion, they did what they could, as fast as they could. You only have to look back to the Falklands, to see what an exocet (much smaller missile) did to a FULL sized Frigate, and then do the comparisons.