There are many questions about miracast. But there is no answer of the supporter. Perhaps Nokia-HMD is not capable of handling this problem. You should buy another smartphone, instead of Nokia, if you want to use Miracast
I wonder why did they remove the notication light from global release..i think it most useful if the nokia can retain the notification light on our nokia phone. Most of mobile phone manufacture remove the notication light. Hard to find budget smartphone with notification light on the market now.
HMD have chosen the stock Android / Android One path. Personally, that is a major reason why I'm interested in their products. That means being extremely closely aligned to Google on most features. Google deprecated Miracast in Android Marshmallow 6.0, in favour of Google Cast / Chromecast.