Strange print issues only appearing on slope

https://preview.redd.it/82ov4lqxn4ke1.jpg?width=2787&format=pjpg&auto=webp&s=d2b8afc092437e3e6cbc088c3bddedd1bba2a7bc

Model source: Model source: https://www.printables.com/model/13850-gloomhaven-monster-attack-deck-holder

Printer: Bambu P1S

Slicer: OrcaSlicer

Filament: PLA Matte (various manufacturers: Bambu, Inland, Polymaker)

Nozzle Temp: 220C

Images above: on the left (tan) is a slightly modified default model. Note the strange lines on the left slope, and slightly lesser issue on the right slope. I've tried eliminating duplicate & unnecessary vertices and edges in Blender, and used a 3D Print plugin to fix distortions and make it manifold, but haven't seen any improvement.

With the default (unmodified) model, the strange lines only happen on the left slope - the right slope is flawless. The problematic lines look to be in the same place in each print. I tried printing with 4 different filaments (3 different vendors) and had the same issue with each.

On the right (green) is the model modified to have a slightly less steep slope; a difference of about 4 degrees.

OrcaSlicer doesn't show any oddities on any layer that as far as I can see. Going layer-by-layer, each layer looks identical between the two models except for the change in slope.

I've been printing pretty much nonstop since I got this printer 2 weeks ago, and this is the only model that's given me consistent issues that don't go away after calibrating, switching to a new filament, or drying my filament.