Thanks for trying,
Odd that you don't see this issue, I tried two broads and the problem is the same.
That is, only when powered from usb cable, powered from battery solves the problem.
Looks like the usb communication interrupts the operation of the board when cable is just plugged in.
So if anyone wants to verify this problem, this is what you need:
470ohm resistor and a led.
And this code:
int Pwm_output_pin_10 = 10;
Power it from usb and see if the led goes on for a short moment, then off, and after a while on again.