https://www.nytimes.com/2017/04/28/us/politics/nsa-surveillance-terrorism-privacy.html [nytimes.com]
But last year, officials said, the N.S.A. discovered that analysts were querying the bundled messages in a way that did not comply with those rules. The agency brought the matter to the court’s attention, resulting in a delay in reauthorizing the broader warrantless surveillance program until the agency proposed ceasing this collection practice.
Though I'm personally wondering why now.