Duplicate transactions happen in the processing world, unfortunately. Bank of America has publicly acknowledged they have an issue and are working on a fix and have already refunded consumers that they have found with duplicates. As @Chris says, labeling this as a "double fail" on Apple Pay isn't accurate and is a bit sensational. And whatever speculation about a patent and second transactions is just that - speculation. This is a bank-side issue in the payment process, not a second transaction or multiple taps or an NFC issue.