It's indeed really surprising to see them _patenting ECS_. Unity's ECS is a lot about cache-friendliness, not just simple entity-compoenent-system, though.
The whole point of ECS is cache-friendliness, so it's kind of the same. Besides there is nothing novel in their implementation. Putting frequently accessed component together is quite an old technique.
Oh, I thought the general definition of ECS is just about how to organize stuff. Or is that EC?