Some portions of the layers will get different color shade  

Some portions of the layers will get different color shade

Hi all,

• Prusa I3mk3s (assembled on Prusa) with some 300h of total printing time
• Some 400h history before Prusa, so I'm rather new with 3d printing
• Prusa firmware 3.10.0-4481 with latest slicer
• Filament: ColorFabb nGen grey, not wet, standard profile setup from slicer, only perimeters bit different between below prints, temp 230 with 85 on bed.
• 0.2mm layer high, standard 0.4mm nozzle, no mods

Case description:

The picture tells more than 1000 words, so the issue is on color getting different on different layer sections. I have two different parts on the pictures and basically the same phenomenon happen on both and it's more than visible or "strong" in normal lightning. I haven much printed parts this size so I cannot say if this something new just came out or has it been since beginning.

Any suggestions what could be wrong? 

STL files below, it's the PSU black power supply holder for Prusa enclosure.

https://www.dropbox.com/s/gy156sirhnpqfbj/PrusaEnclosurePSUDown_medyk3D.stl?dl=0

https://www.dropbox.com/s/ztgsbena3p421sq/PrusaEnclosurePSUp_medyk3D.stl?dl=0

Tried really google this down but could find basically anything related to Prusa, some other plattforms was detecting issue to be on Slicer (Cura) but obviously no confirmation from that.