In my experience you’re better off using the usb3 cable delivered with the laptop, not only will it be much faster (the keyboard uses USB2 I thought), I also think it is better able to power the drive this way. Don’t ask me why but this is from personal experience with the tablet
I am not sure what type of USB the Keyboard has. However connecting to the USB 3.0 port on the tablet is much faster. I am not sure this is going to resolve your issue though. File should open from either USB port.