: If a specific font is causing the issue, try switching it to a standard system font like Arial or Times New Roman before exporting. CIDFont+F1 issue - Adobe Community

While the string itself is a shorthand or log output, it corresponds to a PDF structure like this:

7 0 obj << /Type /Font /Subtype /Type0 /BaseFont /f1 /DescendantFonts [ << /Type /Font /Subtype /CIDFontType2 /BaseFont /f1 /FontDescriptor 8 0 R >> ] >> endobj

This is where CIDFont F1 shines. Because it is often a "base 14" font or a substituted CID font within a PDF renderer: