Hi @PascalKrebs! After looking at the screenshot, it looks like the scene's environment background is reflecting on the metal material applied to the cup.
We are not able to diagnose working files directly on the forum website. Can you email the Stager scene file and log file that you are seeing this issue in to Substance3d-bugs@adobe.com so we can investigate. If the file is under 20 MB you can attach it directly to the email. If it's larger, you can send via a file transfer link like Creative Cloud assets, Dropbox, We Share, One Drive, Google Drive, or similar.
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