Yamaha PW-ST grinding noise when decelerating

[SavvyPavvy]

Hi guys, I'm fairly new to ebikes so I'm not entirely sure if this is "normal" but I've definitely noticed my motor noise has became rather "grindy" recently, but only when I'm coming off the gas and largely in lower gears / eco mode. The motor is new-ish, only 100km on the odo. It's a Yamaha PW-ST which I understand is a little noisy. I'm just worried I might have received a lemon. Cheers.