I've seen this before when lappy is turning down voltages to prevent cpu overheating, what happens is, an app is running and the cpu is getting hot, so naturally the system turns down power. I'd say, plug it in, turn off bios power features. as well in windows and try for a bit. I;'m almost certain its something to do with that. Laptops crank down the power to the cpu for cooling.
No I don't have that issue I have lots of power, power is so important.