Finwing Pixhawk first FPV flight, heavily jammed by another Dji quad

The rainy season here is coming to an end, so it is time to fly this Finwing with Pixhawk 3.1.0 for a spin.
Right after taking off, we have to struggle to trim the plane, as it has a tendency to roll right and pitch down.
Then, someone turns on their Dji quad with 5.8GHz video, and jammed our video signal. This would have caused us serious trouble if we were flying long range.