.eml attachment gets lost on v1.9.12

.eml is enabled in the enduser attachment seting.

However an attached mail gets completely lost.

Steps to reproduce:
- "New email" in Outlook to an Osticket queue
- Drag and drop another email into that mail (just a simple cron report, only text)
- send it

In Osticket only the subject appears, no attachment and no content of the forwarded mail

kind regards
Alexander