Geeetech

Update - After trying to print the xyz cube in a different location it still came off the bed very near the end of the print

I am surprised there are no instructions on how to clean the plate. I have only done 5 prints and the last one, the 20 mm xyz calibration cube, came unstuck and moved, so I printed at a different location. Is this supposed to happen, and if so what are the cleaning instructions?
I have read that ...