Right, ok, so I’m not particularly familiar with Cura… I use SuperSlicer which is a fork of Prusa (which is a fork of Slic3r). Neither slicer has a UI option for initial purge lines as far as I can tell.

So for both Prusa and Cura you are using a block of custom start gcode to define the purge lines? Exactly the same gcode in both slicers?

Could you please share the Cura gcode output in addition to the Prusa version you shared? I am curious what the difference is.