Larger flat area's issues

[solemn sundial]

Voron 2.4 350³
Custom PLA tough filament.

Had very clean and good results with orca slicer calibration parts. Temp test, Flow set, PA set, max flow tested, all good.

Smaller parts printers percectly fine.

Now larger lid for storage container get inconsistent and rsther weird patern.

What i have done:
Z height checked,
Cleaned bed soap and alcohol,
Re-tuned flow on larger test (with close to similair result from basis version),

Base layers all smooth, 3 infill layers (also tested solid) and then 4 top layers. First layer on infill is clean. Then the "top layers" start and these become inconsistent.

Hope someone knows what might be happening

[jovial nova]

I've seen this in the past.
My solution was print faster and more cooling.

Usually, imo, the layer is staying too hot for too long so each successive layer starts curling up "pillowing"

But it can also be a symptom of over extrusion

[solemn sundial]

imma give it a shot

was doing 150mm/s on 8500 accel for those layers. will see if faster works