Assertion failure in PDFsharp: "Should not come here"

[equin0x80]

The attached simple C# code should create a copy of the attached PDF file, copying the pages one at a time into a new PDF. Instead, it produces an assertion failure ("Should not come here") in PdfCrossReferenceTable.TransitiveClosureImplementation, as shown in the screenshot.

The equivalent code works fine with every other PDF file I have tried.

code.cs.txt
2304.pdf