hubmotor loses power for a second

Hi, so I got 3 different scooter, 10" tire air, other is 8" solid tire and a 5.5" solid tire carbon scooter and I notice that 2 of them 8" and 5.5" scooter feels like the hubmotor loses power for 1 or 2 second when jumping it upon landing/hitting pothole/curbs, sudden riding in rough road. It doesn't happen everytime i'm still pulling the throttle when this happens, I'm like what the heck, I let go of the throttle, pull it and it works fine. This happen since day one i got them and have been riding them for a few months now, over 200 miles still works fine but has this issue, wondering if anyone knows what the problem is (no lose wires in under deck on the controller side) or is this normal on small wheel scooter (it can't handle the vibration) ??