In an email thread from 2018, Mosseri checked in with Zuckerberg from paternity leave to try to communicate concerns the Instagram co-founders Kevin Systrom and Mike Krieger had with strategy changes for the app. Mosseri wrote that after catching up with Systrom, it was “hard for me to get a read on what’s going on as the relationship is strained.” He told Zuckerberg, “The core tension seems to be twofold: (1) you believe slowing down Instagram will help more than some others do, and (2) your tolerance for handicapping Instagram is expectedly higher than the Instagram team’s.”