Trailer: ID is not space-separated.

[RenderMichael]

Reproduction:

public static string GenerateNewPdf()
{
    string path = $"outputs/Generated--{NewGuid():N}.pdf";
    using var document = new PdfDocument();
    PdfPage page = document.AddPage();
    document.Save(path);
    return Path.GetFullPath(path);
}

Outputs:

The trailer contains the line:

/ID[<FCEAE9E3BEA9864C83AA492B76687F02><FCEAE9E3BEA9864C83AA492B76687F02>]

There should be a space inserted.

Full file output

%PDF-1.4
%����
1 0 obj
<<
/CreationDate(D:20240522141508-04'00')
/Creator<FEFF0050004400460073006800610072007000200031002E00350030002E0034003000300030002D006E00650074007300740061
006E00640061007200640020002800680074007400700073003A002F002F006700690074006800750062002E0063006F
006D002F007300740073007400650069006700650072002F005000640066005300680061007200700043006F00720065
0029>
/Producer(PDFsharp 1.50.4000-netstandard \(https://github.com/ststeiger/PdfSharpCore\))
>>
endobj
2 0 obj
<<
/Type/Catalog
/Pages 3 0 R
>>
endobj
3 0 obj
<<
/Type/Pages
/Count 1
/Kids[4 0 R]
>>
endobj
4 0 obj
<<
/Type/Page
/MediaBox[0 0 612 792]
/Parent 3 0 R
/Group
<<
/CS/DeviceRGB
/S/Transparency
>>
>>
endobj
xref
0 5
0000000000 65535 f 
0000000015 00000 n 
0000000477 00000 n 
0000000525 00000 n 
0000000580 00000 n 
trailer
<<
/ID[<FCEAE9E3BEA9864C83AA492B76687F02><FCEAE9E3BEA9864C83AA492B76687F02>]
/Info 1 0 R
/Root 2 0 R
/Size 5
>>
startxref
692
%%EOF

[RenderMichael]

I cloned the repo to try and debug through it, and found out this only happens in Release mode.