After having had a very long week of figuring out a lot of other issues after basically remaking a printer, I've finally been able to start printing actual parts again but just ran into an odd issue.
This happened in 3 separate instances that I have seen so far, and potentially more when I am not nearby.
Issue 1: An X or Y move will overshoot a turn it was supposed to make by about a cm or two while extruding, then go back to where it should have turned and will continue on as if nothing had happened, but will leave this random plastic tab sticking out wherever it occurred. I have only noticed it in corners so far, or what appears to be a corner to my eye. Sometimes it happens in the same layer side by side in the walls, or sometimes in the same spot also in the next layer or two.
Example: X axis should move 100mm while extruding, then the Y axis should move 100mm at the end of that move. What happens is the X axis will go 110, then back 10, then do the Y axis move.
Issue 2: When an axis is moving (again in a straight line) it will stutter the whole way down, or stay in place until it should have finished, then travel to the next point and continue as if nothing happened. On one occasion it bounced back and forth a few mm while extruding, then stopped extruding and traveled to the end of the line before continuing as usual, but with a blob in one corner and no filament in the wall path after it until it got back on track.
Examples: X axis should move 100mm then Y axis 100mm while consistently extruding. What happens is it will do one of two things, seemingly randomly (but repeatable with the same .gcode, or even same stl):
-A. X axis moves forward 3mm, back 1mm, forward 3mm, back 1... until about 75mm, then will stop extruding and move to the end of the X move and start the Y as if nothing happened, leaving an over extruded pattern the first 75mm, then nothing the last 25.
-B. X axis moves forward 1mm, back 1mm, forward 1mm, back 1mm, until I assume it thinks it went 100mm, leave a blob, and then move to the end of the move before starting the next line on the Y axis.
With all of these, there haven't been any layer shifts, or really anything that significantly affects the finished print, except the extra tabs that need to be pulled off, or a blob/missing line somewhere. However, it is incredibly annoying and I would rather not have to worry about this kind of thing if possible.
I put the .gcode files into a few online analyzers to see if those moves show up as an error in the slicer (Cura 4.10.0, MacOS) but aside from everything looking funny in those viewers, nothing looked like my issue. Reading the files didn't show that as "intentional" either, so that leads me to think that I either missed something in the .gcode file, or the Duet board sees a particular move or variables and interprets it the wrong way.
My setup is more or less a stripped Ender-3 Max frame and steppers, a belt driven Z mod, and a Bondtech LGX Flexibles direct drive all tied into a Duet 3 Mini, which so far has worked very well. I am on the most recent stable firmware and DWC 3.3, if it helps. If any of this seems familiar, I would be very glad to get some help as I haven't found anything like this online yet. If requested I can try to get some decent pictures of this soon.
Thanks!