Strange travel from clearance plane

[[Pa...]]

There are a few programs here that were written before my time.  In many of them I see a move that I don't know how to do on purpose, and I hate when it happens by accident.  I've got a really good sense of how the retract and clearance distances work.  I understand the sequence of stops along the road from CP to probing and back.  

We always have long shafts with long axes oriented along Y.  We very frequently come down from CP+Z to Z zero at CL of the part in order to scan the upper 180° of the shaft.  I'm quite comfortable with verifying my rotations to ensure a 180° scan starts at 90 or 270 as appropriate, and that I'm never looking to reach around or under onto the back side of the stylus sphere.

In some old programs, the stylus pierces CP+Z and moves in a straight line along Z to the retract distance, which is what I want.  In others, the stylus pierces CP+Z in a huge arc move; tracing a portion of a spiral that starts at the CP and persists all the way down to the retract distance.  In all examples Clearance Distance is zero.  In all cases we're using a stylus system with a single stylus to Z-.  They aren't the same stylus though; different tip diameters and lengths across programs.

Recently I programmed a sphere offline as I always do; one of 4 in a small program.  When I got to the machine, 3 of them worked just as expected with straight line moves from CP to retract, but one sphere approach did the huge swoop, hellbent on colliding with every feature in the measuring volume except the one I wanted to evaluate.

The really strange part is that I programmed only one sphere.  I then copied that sphere and adjusted the nominal locations only; all sit at the same Z height so I adjusted X and Y only.  I literally never opened the strategy window in the second sphere.  The strategies for all 4 spheres are the same as I only wrote them once.

Measurement Plan Editor Features has an option for Arc Motion mode which I've not explored and do not understand.  All we need to know here is that every program I've ever written is defaulted to "on", and that changing it to "off" had no effect that I could see.

"Form related travel within Strategy" is another heading in the editor.  Again, I've not explored this yet, but everything I've ever written has this defaulted to "off", and turning it on had no apparent effect.

This move does not occur in simulation, but it does occur on both physical machines every single time in those programs that use it. 

I used some position points to get down where I needed, so I don't have a lingering problem I need solved.  Anybody know where this move might be coming from, or how to avoid it?  It's baffling that I cannot spot anything different yet there it is.

Below is my current system, though this "feature" has been present since 2015 at least.

CALYPSO 2024 , ServicePack 5
Version 7.8.20 (27.10.2025)

Accura 16-42-14 and Accura2 16-42-15, both with VAST Gold.

[[Da...]]

A clearance distance of 0.01" eliminates the arc motion for me.

[[Ma...]]

Wait - there is more - https://youtube.com/shorts/N9TO4b0frDQ?feature=share

This movement was due negative depth in strategy. Changing vector on a sphere and make it positive numbers in helix depth was a repair.