I have suddenly encountered my machine (a modified Omio) sometimes goes to far in X. Yesterday I routed a piece were there should be a square hole in the material but suddenly it went too far to right in X. After going down several passes correct it suddenly went 45 mm (approximatelly 1-12/16") to the right.

This also happend some weeks ago but mostly it performs nicely. So where should I start looking? I find this strange since it seems to add steps rather than loosing them.