In common with thousands of other people we are still having this problem.
I don't believe anyone from Microsoft monitor this or the W10 Feedback Hub.
Like you we have 3 MS Designer Keyboards connected to different laptops - all have the same problem since the Fall Update. To make matters worse my own machine is a MS Surface Book - so Microsoft can't even make their own hardware work properly together.
I know what not to do next time I see a glossy MS advert for yet more Surface products...!
David.