https://www.cnet.com/news/court-docs-reveal-apple-knew-about-iphone-6-touch-disease/

According to the public documents, which were obtained by Motherboard, Apple's "internal testing 'determined that the iPhone 6 was 3.3 times more likely to bend than the iPhone 5S ... and that the iPhone 6 Plus was 7.2 times more likely to bend than the iPhone 5S." 

"One of the major concerns Apple identified prior to launching the iPhones," Judge Lucy Koh wrote, "was that they were 'likely to bend more easily when compared to previous generations.'"