I posted in another community on Lemmy and got some suggestions, but the only that that's make a different so far is printing a lot slower. That decreased the underextrusion area to about half, but it's still there and very obvious on ASA.

I'm leaning towards a bad extruder (or at least bad gears), but they're BMG and I don't feel like they've had that much usage yet. I might take the opportunity to replace it with a Galileo 2 and see what happens.

If I end up figuring this out, I'll come back and reply again.

I finally solved it. Voron KAMP's Voron Purge technique puts little blobs of filament on the bed. I also have Voron Tap. My tool head was hitting those blobs and moving upwards slightly, causing the extruder not to squish the filament into the bed in the same pattern as the voron logo from the purge.

My solution was to initially to move the purge further way, but that kills large parts of my bed usage. So I just wrote my own purge line script and I'm using that now.

I hope this helps you solve your problem!

Fellow 2.4 person whose also chiming in on the thread in the lemmy.world instance of this community. My 2.4 doesn't do this, but it could potentially be klipper related (pressure advance, input shaping, etc).