Google recently began the Android 8.1 update rollout to Pixel series and some bugs in the update have surfaced. Multiple users reported the issue in Google issue tracker and also on Pixel community. Despite the exclusive features like Neural Network API, it seems that Android 8.1 Oreo contain some bugs too.
The Multiple Touch break bug has been reported previously while testing the Developer preview of Android 8.1. But the bug makes its way to the consumer release, some how.
When the user touch the screen with multiple fingers, the image on the screen shakes and jumps. So while playing high fps games or using pinch to zoom feature, the break of multi touch feature is visible clearly. But it is not known whether the bug affected only some Pixel devices or the Pixel 2 and Nexus 5X devices also got affected too.
Fortunately, Google already began looking into the matter and the bug fix will be on the way soon. Orrin, the Pixel community manager says that he is investigating the issue. So the fix for the multi-touch bug may come with the next update.
If the multi-touch feature breaks in your device too, you can report it through Settings > System > About Phone > Send feedback.
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