Got really busy and didn't address this issue, I took the car to the mechanics, they drove it, noticed the noise, and then put the car on the rack. They couldn't find what's wrong, CV joint, wheel bearings, and other suspension components all appear to be okay.
The noise is still there, it magically appears right after I accelerated pass 49mph, but the rhythm and noise level stays the same regardless of speed (I've varied speed between 50mph and 80mph). The car still drives normally, no shaking steering wheel and alignment is perfect. The only thing I can feel besides the noise is very minor vibration accompanied with the noise, so minor I can only feel it if I drive in my socks.
What is belt in the tire? The metal reinforcement belts, or some of the rubber grooves?
2013 LEAF SL w/Premium Pkg, Brilliant Silver, 55,244 miles, LeafSpy: 50.17 AHr, SOH 76%, Hx70.30% as of 11/05/2018, 10 bars, 28 QC, 2129 L2/L2