IFixit has a good article on it. Basically they couldn't get it to pass wireless emissions standards the way they wanted to do it (put your phone anywhere on the pad to charge not, not directly on the circle, etc).

Would be quite rare for a patent dispute to go on behind the scenes. There were a lot of leaks suggesting mass production was due to start. I would bet production did not start, and that early production runs had low yields due to the complexity of the product.