We received s-mime certified mail with attachement with the pipe-character in the filename.
We can reproduce this behaviour when sending e-mail from Mac Mail actual version, attaching a pdf with a pipe-character in the filename, and using html in the mail body signing the mail with ssl certificate.
In Outlook 2013 the mail is received using pop3. Opening the Mail gpgol is reporting in German:
Nicht alle Anhänge können angezeigt werden. Die unsichtbaren Anhänge sind: Grund:
clicking ok and opening the mail, only the mail body is shown no attachement is shown.