This is nonsense.
Hawkeye came out and issued a statement immediately after the match that the system was turned on and working normally (it was reporting "goals" when the subs were shooting into the nets at half-time) but the specific circumstances of the incident were such that the technology wasn't able to triangulate the position of the ball (due to interference from the players and post) and therefore a goal couldn't be signalled by the technology. It was, apparently, the first time this had happened in over 9,000 instances.
Well - Thats me told !