Problem with Edge 1040 in combination with Elite Rizer Smart Trainer

Hi,

I am using the smart trainer Elite Suito together with Elite Rizer. The rizer can simulate a grade from -10 to +20% and set the difficulty.

The trainer is connected to the edge 1040 as trainer and listed in the sensor-list. Fine so far.

Now I can start a training with setting the grade e.g. 3%. The trainer rizes up for abbout 20 seconds and then levels down to 0%.

I don't know why he is doing so. This don't happen with zwift, only direktly from garmin device.

Someone a clue?