Shift in Y axis 50% through print

[TheFlapjack 0]

I'm using Cura 4.9.0 with a Geeetech A30T.

At 50% through the print I'm getting about a 2mm Y axis shift in the base for the rest of the print.

Happened with both of my first two attempts at printing.

This shift is not apparent in the original .stl model or the preview & slice.

I have no idea if this is  Cura setting issue or a Geeetech printer issue, so checking this with both parties. 

Thanks.

[IRobertI 521]

If the shift was happening in the gcode you would see that in the preview in Cura. It's very unlikely though. More likely is that you have a loose pulley or something along those lines. I'm not familiar with that particular printer but I would check that all your screws are tight and that the belts have proper tension.

[TheFlapjack 0]

Thanks, I checked but couldn't find anything loose.

Printed the object again but rotated 90° and it printed correctly.

Since then I've printed different models and the problem hasn't reoccurred.

It's a mystery !