Hood,
By overrun I mean it is driving the steppers so hard it actually loses steps. It will happen with any axis. But it will only do it with certain programs. It acts the same as if you are in motor tuning and have the velocity too high. It will miss a lot of them and be off by many inches (centimeters). It only happens at tool change. Going to or when returning from. The tooling is not any different than other programs I am running. I have looked at the G code and it is the same calls that are in the other programs. The only thing I noticed but I do not remember if it was normal was that when I load a program and it say generate toolpaths, that dialog process bar will complete really fast but until the program is ready to run is a while afterward. So why would it do this when all toolspaths are output to a single file but if you output a single toolpath to a single file it will not. If you output all toolpaths to a single file again, it will rapid so fast to over drive the steppers. I have loaded gcode, over driven, closed gcode, loaded again, still does it, powered down for several minutes, restarted tried again, still over drives, load another program, works fine, load that program again, over drives, load only a single toolpath, works fine. I almost give up.
Sorry for the long rant, only trying to give you the steps I have taken so far.