Dynamic resistance up and down

with my home trainer tracx flux s I have a fluctuation of the dynamic resistance, whether in classic course or training I use a connection via zwift companion

I have crash/down of resistance (sometimes in same ride, nothing)
So I pass my time with (exemplary) 150watts 70watts
Every seconds
Do you have some answers ? Ant + ?

Is the image showing an ERG workout? If so, are you keeping your effort fairly steady? I know I will sometimes let my attention drift from holding a pace, and then I’ll be greeted with a sudden increase of resistance, be it from decreased cadence in an ERG workout or just a hill in normal riding.

it means that I film the sudden change in the watts the next time but no, it’s about the second or the resistance disconnects and reconnects
You can see the white line up and down but it’s so tight that it makes a big white thing