Hi,
I have this issue the longest time (mine is Asus T100 CHI), and this article below seems to resolve it for good!
https://mikebeach.org/2014/11/29/fixing-frequent-bluetooth-disconnection-on-asus-t100/
Basically, you go to Device Manager and disable the Power Management option for Bluetooth. So it is actually the bluetooth problem of Asus tablet, not the keyboard!
<<Always thought the Dock is bad, i bought another bluetooth keyboard to replace it, and then saw the same problem!! then i realize that’s why my bluetooth mouse also seems flaky… now i know it is actually the bluetooth of tablet’s problem (well, not the hardware but the driver and the power saving option, apparently)>>
Try it and i hope it works for you all too!
Cheers,
Stephen