A1 print faults (unevenness in every print) – what could be the root cause?

Hello community,

I have a Bambulab A1 printer and I have a problem in nearly all prints:

  • Detailed description of the problem
    → There is an uneveness in the structure, see attached picture.

  • Printer model used
    → Bambulab A1 with AMS

  • Slicer settings used
    → Standard PLA Basic Slicer settings of Bambu Studio

  • Type of filament used
    → Bambulab PLA Basic (black)

  • Photos that clearly show the problem
    → See attachment

Can anyone tell me what could be the root cause?

Many thanks in advance!

Best regards,
Bluesky