I dual booted Win10 and Ubuntu on my laptop and I could only use the dedicated graphic card in Ubuntu if I turned Windows off with the power unplugged. Maybe that was a symptom of similar properties?
Windows 10 doesn't completely turn off by default anymore. It closes all the applications and then hibernates the Windows system stuff so doesn't need to re-initialize everything on boot. There's a way to fully shut down but you'd have to look into that.