That pixel blinking is the Proximity sensor and it's activated automatically during calls so that the phone can detect whether you are using it hands free or not and lock the screen accordingly
And I can't see the lag in that Uber app transition. Maybe it's not getting captured in the video perfectly
normal it is, not a single one is the problem , the uber one is u talk about is the ghosting because of the pixel and screen is totally black so it is normal , one with blinking is the sensor which is visible when u dial a call.
We would like to inform you that the blinking of light during the call is the normal phenomena or it is a work of proximity light sensor in the device. Whenever you are on call you can see the small blinking of light due to a proximity sensor, so this is not an issue.
Further, to resolve the uber lagging issue, please perform the below mentioned steps:
Perform the clear cache of app (Settings>>apps>> uber app>>storage>>clear cache)
Perform reset setting (Setting> General Management> Reset>Reset setting).
Check the internal storage of the device and clean it (Setting> Device Care>Storage> clean now).
