A dislocated print sheet usually is an indication that a warped part or a bit of overextrusion was caught by the nozzle, and the forces involved were strong enough to dislodge the print sheet from its magnets. PETG is prone to warping, so here might be the problem. My solution to this can be found here:
Aside from that:
Try a slightly higher Z-offset if this already happens at first layer
Try to avoid cold air hitting the print, and let the whole system warm up. Warping is caused by too much cooling in short time.