tl;dr: iPadOS 27 broke a key presentation workflow: when AirPlaying, tapping any app other than the presenting one now mirrors the entire iPad screen to the external display, exposing private notes, poll results, or presenter views. This affects GoodNotes, Keynote, and PowerPoint differently, but all are disruptive—Keynote exits presentations entirely, while PowerPoint enters a broken state requiring a restart. The author proposes that apps in presenter mode should retain external display precedence until explicitly stopped, and has filed feedback with Apple (FB23615646).