This kind of issue has cropped up in previous versions so it seems to have regressed. I don't know what differences the flavors make but I can't get extrusion to behave. I think I found out how to set cura to issue relative moves for the extruder in the "special modes" settings but the E motor is skipping furiously when attempting to print with Marlin flavor.
Back to PrusaSlicer for me now. 🙄