Resistance out of control

Hi all,
since 3 weeks my Zwift Hub is loosing restistances control when ever it likes to, it can be half hour in can be 2 hours in but at some point the resistance drops to zero, I use virtual shifting and when I gear all the way to highest gear it most of times re engages for a bit and drops to zero again. I switch of all surrounding devices that can cause inetrference, all hard and software is up to date.

it becomes undrivable the hub is only a year old, coulkd it be broken

please help