can't find last xref section


I get this result:

~~~
> pdfcpu stamp remove a.pdf b.pdf
C:\Users\Steven\AppData\Roaming
writing b.pdf...
optimizing...
pdfcpu: no watermarks found

> pdfcpu stamp remove b.pdf c.pdf
C:\Users\Steven\AppData\Roaming
writing c.pdf...
Read: xRefTable failed: pdfcpu: can't find last xref section
~~~




