I would guess that it is not a slicer issue but a hardware issue... but thats just a guess as I can't think of any setting that would do that, looks more mechanical that slicer error.. If you are not printing them at the same speed then it isn't really much of a comparison.

This has been talked about over the years and it sure does not make sense how it is. One work around is to multiply the layer number by the layer height and you will then have the number to plug in to the start and stop. For instance if you want to change infill at layer 30 and your layer height is ...

If you are not using 1mm resolution on the supports, give that a try along with the other items I suggested.

manually add more supports around it, add 6 solid base layers, add a skirt of 5 outlines .04mm from the part. This brim will come off fairly easy if not over extruding and will help to hold the supports. Hope that helps.

just for fun set first layer height : 100% , width 100% speed 30% and see if that helps

Glad I could help!

edit the process, advance tab, top left uncheck the stop printing option. Check out the docs on how to use this feature as well as grouping process

Advanced tab, change from gapfill to allow single extruded fill and see if that removes the gap fill Zigzags

I have several parts I sell that slide on a machined rod that contain round and rectangular holes. To get accurate fit, round holes must be .45 mm larger than the rode within the model. At least with the way I calibrate my machine. With a smaller nozzle and extrusion width, the less the difference. ...

I would suggest you reprint it with cura and see if it is as nice as it was before. Almost looks like a mechanical issue rather than software.. Then again, I did not upgrade S3D and can not say for sure as there are apparently still many issues with the current version.