DCMTK

Dcm2pdf sometimes incorrectly removes the last byte of the pdf.

See dcm2pdf.cc line 315 and further:

315 /* strip pad byte at end of file, if there is one. The PDF format expects
316 * files to end with %%EOF followed by CR/LF. If the last character of the
317 * file is not a CR or LF, we assume it is a pad byte and remove it.
318 */
319 if (pdfDocument[len-1] != 10 && pdfDocument[len-1] != 13)
320 {
321 --len;
322 }

Some pdf files do not end with a CR/LF character after the %%EOF marker.
When this is the case and there also is no pad byte, the code removes the 'F' character (from the %%EOF marker).

This topic is also addressed by DICOM CP 1851 (January 2019 voting packet).