A
Haven't seen this, though even before Nougat this would randomly stop working. Disabling and re-enabling it in the Moto app always brought it back.
Fwiw, this simple feature I use daily is one of three Moto exclusives that keeps me from moving to Pixel for its better camera. Other two are twist for camera (incredibly useful when touring on vacation), and Moto Voice recognition from sleep.
Why doesnt chop chop motion work on flashlight after nougat update turbo2