Layer shift on one model

This is first time happens with my printer. I started printing two parts and went to my work. After came back I saw, that layers was shifted (1-2 photos). Well, I thought that maybe it was a short electricity surge, or something about. I've started printing again the same .zcode file. I have the same result (3-4 photos, I stopped printing when saw shifting). I thought, maybe problem with file, or printer/zsuite/etc don't like print 2 parts at once. So, I create zcode file for each part and start printing again. First part prints well. But second has the same shift (last photos, grey ABS).
Need help to resolve this issue. 

Check your GT2 pulley, a screw need to be thighten