Power readings differences between erg Mode and Resistance

I have a kickr 2020 and normally train in ERG mode with powermatch so my workouts report my bike power meter readings SRAM Red AXS, I also always have second device taking the power readings directly from the kickr and found a normal 2 to 4% higher readings as suppose to in the bikes Power meter.
Recently I start training in resistance mode and powermatch mode same configuration but when using resistance, the difference between the Kickr power and the Sram AXS readings went much higher up to 8-10%.

Any ideas why this is happening, is this normal?