action_rebuild modifies quoted-printable attachments even if part should not be modified

[bigio]

If in the email message there is a quoted-printable attachment and it's not been modified by mimedefang-filter, when MimeDefang runs action_rebuild it forces all lines to 76 chars thus modifying the attachment.

[bigio]

quoted-printable must limit lines to 76 chars, it seems Microsoft Outlook creates quoted-printable attachments with lines longer that 76 chars, so in action_rebuild the attached file is reformatted correctly even if different from its origin.
This could break some digitally signed pdf attachments.

[dfskoll]

Do you have a test case you could share?