If you notice that your prints are twisting slightly there is a very simply fix to this. Sometimes oils or dust can build up on the contact points between the heated bed and the printer which cause there to be less friction holding it in place. There is a simple fix to help solve this problem and all you need is a little bit of rubbing alcohol. The picture below is a before and after picture when we had this problem here. 

1. Take off the heated bed by pushing backwards against one of the bed clips until you can slip the edge of the glass bed past the lip and lift it out.

2. Take a cloth and some rubbing alcohol and wipe down the exposed glass on the underside of the bed.

3. Look at the bed clips and carefully clean the clear sensor pads like the one shown in the picture.

4. Replace the heated bed by doing the opposite of what you did to take it off. Place the heated bed into place and then push one side of the bed clips back until the heated bed will slide past it into place. 

This should remove any oil or dust build up on those contact points and should keep your prints from rotating anymore. 

Happy Printing!