I didn't shrug it off as a nonsense, you misunderstood it in the first place and well, yes my phrasing was quite directly wrong there too but like said I just meant that there shouldn't be any difference between this top layer and other layers.
My idea of this thread was just to ask if others have noticed similar thing (besides the normal under extrusion issues) and if there could be, if not a bug, then something "unideal" about my settings combination that I've missed (some weird way thin walls could interfere or something) but yeah, maybe it's just a combination of this part and material that arouse this issue so clearly. I'm surely no expert of non newtonian fluids but not all amateur in 3d printing either. I kinda hate having some magic factor to fix issues when everything should, in basic theory be in order but hey such is life
Speed does affect this for sure but again it makes me think that there's something wrong in parameters elsewhere as the multiplier should scale to all speeds but again, not an expert so maybe it doesn't. It'd just mean there's no way to perfect the prints ever as things would get over or under extruded depending on the speed of the section.
About mainboards, yeah well, you get what pay for I guess. Like said I noticed this whole thing accidentally while troubleshooting other issues. For some reason my extruder decides to quit on certain parts, always exactly at the same spot and like said I don't have the LA active that would explain it. It's so exactly at the same spot that a HW issue is pretty much ruled out. There's a ticket about it on Marlin repo open and it's still fresh but still have a funny feeling it'll never get sorted out and I have to get another board, which then would logically be a Duet just to maximize the chance of getting rid of this random stop issue (and the chance of getting several new ones).