Update 2: tl;dr: had to turn off (or maybe tune) z contouring.

So after looking at it and pulling it apart and several times missing the window to go look as its happening, it looks like it wasnt extruding enough to actually stick, eventually there is enough of a ball that it sticks and it repeats causing that pattern.
I literally just found out after idk how many years of 3d printing that the post slice view can be switched to visualize different things including flow which coloured specifically those areas blue or really low, like down to 0.1 even. Going through everything one by one to make it consistent flow, it turned out to be 'z contouring' was on and presumably very misconfigured. I still cant believe it wasnct the broken extruder. I even threw the bmg clone and calibrated it to get the same results as the repaired pap lite.

Update: Shockingly the broken extruder that was somehow still extruding wasn't the cause. I printed another a4t shell and the same areas have that defect. It seems to occur mainly on just the exterior wall of both inward and outward overhangs but parts of the same section dont have it, and this model is the only one I've seen this on. I'm waiting for the printer to heatsoak for further testing but at 3 teardowns in, I'm just guessing now.

Edit: It was the extruder. One of the belt gears sheared off, and there was enough friction between the pieces that it still worked at slower speed, even well enough for the calibration test prints I tried. I had spares that I printed ages ago and now it works.

I started getting this weird exterior wall defect that I haven't seen before. Calibration testers come out clean though and it's driving me insane.

Using orca slicer with an e3 switchwire trying to print parts for my other printer so I can rebuild this one into something not a switchwire.

Looks like some extrusion issues, at least for the stuff along the vertical walls. my initial guess is clogged nozzle, though it might also be temperature issues

I guess I'll burn the last 200g on this roll going through the whole calibration suite again while the last one is drying

I'm taking a complete shot in the dark, but it's happening on the X and Y axes and what looks like similar spots every layer, which makes me think that'd it be something mechanical that's only manifesting under some condition (like flow rate or speed). Maybe check your bolts, belts, and rails? My gut says loose toolhead/ extruder (wiggling could cause weird lines like that), but that's more a guess than an "I've seen this before" kind of thing. Failing that, I'd be curious to see if that pattern shows up in a flow rate test.

I know many folks have sworn off Discord, but if you haven't, maybe try asking in the Voron discord too?

I think it would be worthwile to lower speed on overhangs and add more cooling on overhangs. That should clear up those patterns.

Woo! Congrats on pinning down the source!