I bought a cube mix plus from aliexpress last month and just got it recently together with its keyboard, cdk09. I have the same problem, the magnets somehow repel the tablet from connecting to the keyboard. Have you a solution to this already?
So I was going to open the tablet anyway to do the thermal mod. So when I opened the back of the the tablet and it turns out the magnets on the tablets were flipped. I flipped them the other way, and it now works fine. you can see the magnet from the video for the thermal mod: https://youtu.be/AOd-ZI9YbMU?t=3m52s