I running some 251 Geckos with Mach3. After a RESET, when I hit RESET to get things going again, the steppers will give me the little bump sound, but sometimes will also move a small amount. It's not consistant, usually about .004" or less, but has been as much as .010". It's always in the same direction - negative. The DRO on the screen never changes. I have not tried to see if the STOP/START buttons react the same. This is not something new. It has always done it, but has not been a problem. Now that I'm learning more, it is a problem. I'm pretty much a rookie with Mach3 and CNC on this home built machine, but so far it's been working pretty well. Any ideas on how to solve this issue or is it normal?  

This is a function which can occur when an axis is disabled / enabled and it is the result of the previous micro-step position of a stepper motor controller being lost and the stepper motor then moving to the nearest whole step position. Basically it is normal behaviour.

Tweakie.