I have printed PLA with 5 perimeters and 50% hexagon infill.  Nema 23 version. 

I put 2 of the support feet from one side back to back on a flat surface and noticed a few millimeters of difference at the top.  The other side was the same.  This would try to twist the Y rails if left as it is so I will sand down the bottom of the feet to make them square and identical. 

I assume it is a little warping in the prints and not the models.

Has anyone else checked this and if so do they have a similar error?

Yep mine warp a little too ! its only really the z cradle that maters ! Print the bits that don't mater down and try keep your room temp even we had few very cold nights here a few weeks ago and mess mine up, 

Tip try and print them all the same way I had probs with the Y tops I printed them the the other way to the bottoms and sight diff in slicer or shrinkage and they didn't line up quite right Oh and the Y sides you may need have to add washers between as the wheels I got in the uk were little bigger and it was too tight to slide easy 

I slow down the print to mid setting and .2mm layer high and it help ! (and as long as you can get the Ally in the holes !! )

(Its still quick to print slow than twice )

My setting 

Ender 3 with prusaslicers  215c first layer 210 rest 45 c bed temp .2 layer hight and brims (support is only need for top  z to bit) But i did have lot problems with cheep rubbish filament but it was all I could get the time basicfill of amazon is working well at min for me ! 

hope this helps 

welcome to email Emearg@zoho.com if you stuck I am just about build just waiting for my steppers to arrive  

Thanks emearg,

I had thought it was warping but I don't think it was.  I found the X/Y was not perfectly square.  It was a fraction of a degree out.

I have adjusted it now but don't think I will print everything again!  Just make a couple of shims.