At the present rate of progress, this should be ready for market just about in time to replace my worn out Alta... I had best put some additional effort into wearing my Alta out.
It's normal, at 430 hrs and 7500 miles there's been no issues with mine. It seems to sound worse after a bit of riding and the motor is a little warmer.
so put your worry beads away and ride.
I have encountered something similar when charging in the winter when the battery is below 40°F. But after things warm back up and I get a few more charge cycles completed, it's all back to normal.
I'm surprised that the predator 9500 cannot do 2 bikes simultaneously; when we do our 24hr race we use one Honda eu7000 and it can manage 2 bikes at once. And the eu7000 is only rated for 5500 W continuous.