Our development team is currently investigating this as a number of people are reporting that they are experiencing that the Xperia™ X Performance has issues with the accelerometer, gyroscope, magnetometer, ambient light, proximity and the barometer. The auto screen rotation also may not not work anymore. As a workaround, try to restart your device. We are working on a solution. A new software version will be available within November, 2016.
Note! Software rollouts are a phased process – timings & availability may vary by market/carrier.