A search in this forum will reveal that there have been instances of various degrees of noice coming from the hub. I just opened a Tech Support case with Juicedbikes to see if we can correct this. I purchased the bike on August 20, 2019 (about 20 days ago) and it has about 140 miles on it.
In the video the grind does not sound like much but in real life it does not sound normal. The bike just started doing this noise and I have confirmed that it is coming from the hub. It is random (comes and goes) under all circumstances (pedaling, gear, assist level and using the accelerator).
I will be traveling for a month with limited internet access but any feedback will be appreciated. I will keep you posted on Juice's response to my request to exchange the rear wheel.