In short: Android 9 Pie has some serious issues with consistently hiding lock patterns when users tell it to, according to a number of reports posted on Google Product Forums and social media in recent weeks. As illustrated in the video below, the system-wide setting that promises to hide the pattern doesn't appear to be working consistently for unknown reasons. While the video appears to have been edited, dozens of users reported having issues with similar behavior, though the Mountain View, California-based tech giant has yet to respond to the claims. Owners of the second-generation Pixel devices and the Nokia 7 Plus, both of which run a stock version of Android 9 Pie, claimed to have experienced problems while trying to hide the lock pattern of their devices.
Background: Originally launched via the stable channel this summer, Android 9 Pie is the latest version of Google's omnipresent operating system that revamps a lot of system behaviors with the goal of improving battery life, user efficiency, and other aspects of using contemporary mobile devices. As is the case with most OS upgrades, the initial build of the software introduced some bugs to select handsets, with most major ones already being addressed by Google. The last revision of the OS came in the form of the October security patch that also debuts some bug fixes, though none of them address the inconsistency with hiding lock patterns.
Impact: Given how the newly reported issue appears to be affecting devices from multiple manufacturers, its cause is likely related to the OS itself and not any particular implementation of the thereof. Due to that state of affairs, Google should be the one fixing the problem in the coming months and will most likely bundle the solution with one of its monthly security patches, the next one of which is scheduled to be released on November 5.