Need some help setup a job on my Helix 24X18 to engrave house numbers on a 18X12 granite tile .Run a sample on a brown paper works perfect put the granite in engraving from bottom up get to about 6 1/2 inches up and the print goes off line by 7/8 on a inch little wavy then it runs straight .Stop the job send it home of home in the X by 7/8 inch shut of laser restart run a small box it is perfect.Run another test this time off by .050 .Epilog said could be a bad encoder strip change that same thing. Any one have this problem. Will add photos if that will help to see what is happening