Some progress...
I have tried padding out the code with waits, just in case. Couldn't wait so i popped out and fired her up, no change
The macro i am testing is a more complex probe tip calibration ring thing so more chance to spot a pattern in the mess-ups. After staring at the code and the sequence of what happens I noticed this....
It would do the fast probe perfect, then step back, then do the slow probe and from then on it was pants - total mess
Now, when writing it I foolhardily presumed that as I was switching from +travel to -travel it would NOT need a step-back move - WRONG - it seems you MUST step back before issuing another PROBE call - my guess is that as the previous call ends, the probe is left touching the surface and as soon as the new call goes in, it activates the probe first, sees the existing contact and thinks “job done” without moving, from then on it just gets worse.
I added a step back after EVERY probe call and it works!
So, I thought I was on the home run, went to close Mach3 - I always press reset first before closing, so pressed it and Mach3 just bombed out back to windows.
two steps forwards, one back
at least part of it is positive i guess