Drag and Drop emails to PC: PDF's are corrupted

I am used to save specific emails with PDF-attachments on my (Windows) PC/network by dragging them to a folder. That was going fine with Windows-10, but since I started using an new PC with W11, the dropped emails with PDF attachments give an error when the PDF is opened: “Format error, not a PDF or corrupted”.

When I use ‘Save as’ from eM Client, then it goes well. PDF’s are good when opened from eM Client too.