I wonder what would cause this error on my parts. Till recently, all worked well, but on my last 5 parts i noticed error on x axis. It is the same error on all 5 parts. It is cut circle and there are also 40 x 7.1mm holes made circular around that circle. Error is 0.5mm only on x direction. See the illustration bollow what i mean:

https://i.imgur.com/wB1vJnK.png

The holes positions have same error, so i assume it is worn leadscrew / nut, but when i move the x axis by hand, i dont feel any movement, so i wonder, is this mechanical error or is there some electrical issue? i use chinese servo motors (bst motion, krs?? 400w) and cslab csmio ips controller.