CNC drawing arduino

I have made CNC drawing arduino machine.
First,everything is ok,
but when I was about to perfom it
The starting point always is not precise
if would be distorted for seconds.
but! after the moment.
the machine could be fine.
I want to ask why it work like that?
and how could I solve it ?

thanks a lot

Don’t put the pen down before you have reached the starting point of the drawing?

OP’s image

how is this a website and forum question?