Smudgy/ripply top layers & solid infill

Any ideas where these smudgy top layers come from? Especially the corners? It's a VC3.1 400, enclosed, Rapido UHF fed by Orbiter. PLA, printed after excessive heatsoak, 0.6n, 0.4lh I did: tune PA, checked my rotation distance, calibrated flow, reduced extrusion width on top layers and top solid infill to 0.41, reduced infill/parameter overlap to 5%. Sliced with PrusaSlicer 2.8.0