tillig

I've been struggling with printing a calibration cube recently on Cura 4.12.1 on Windows. Wherever the z seam happens, there's an under-extrusion issue. I'll attach some pictures to show what I'm talking about. If I randomize the z-seam it becomes less obvious, but it's still there. I can disable retraction entirely and it's still there, so it's not a retraction issue. If I use Prusa Slicer for the same STL, I don't get this issue, so it's not an STL problem. I've tried different temperatures (from 190C to 220C) and it doesn't matter - it's not a temperature issue. I've tried different filaments (different colors and brands) and it doesn't matter - it's not a material issue. I've tried both the default standard (0.2mm layer) and dynamic (0.16mm layer) profiles and it doesn't matter. I do have a direct drive extruder and an all-metal hot end, so retraction values are shorter (due to direct drive) and temps are usually hotter (due to the hot end) but, again, based on the tests I've done it doesn't seem to matter. Is there some setting I'm missing that has to do with z-seam and reduced flow rate? Is it related to this gap in the z-seam topic?