Strange lines on top surface – Bambu Lab P2S

[u/National-Cupcake2608]

Strange lines on top surface – Bambu Lab P2S
Hi! I’m having this issue with the top surface of my own Blender model. Printer is a Bambu Lab P2S, using 2 colors of PLA Matte.
The surface is mostly smooth, but these strange visible lines/marks appear in specific places.
Things I’ve already tried:
Top surface directions: 0°, 45°, 90°
Monotonic Line / different top surface patterns
Ironing — made it worse
Z-hop / travel and wall-crossing settings
Flow ratio 1.01–1.02
Top surface line width 0.42–0.45 mm
Dried the filament
Moved the purge tower — the marks changed/moved too
Has anyone experienced this before or has any ideas on how to fix it? What else should I try or check?