Outlook attachments can't be viewed

Checklist

• I have used the search function to see if someone else has already submitted the same bug report.
• I will describe the problem with as much detail as possible.

App

Thunderbird for Android

App version

14.0b2

Where did you get the app from?

F-Droid

Android version

Android 16 QPR2 Beta 3.1

Device model

Pixel 9

Steps to reproduce

Receive an E-Mail sent by Outlook (with uncertain settings) that contains forwarded emails (probably forwarded as a file instead of just embedded into the email).

Expected behavior

The attachments should be properly displayed, as e.g. Thunderbird for Linux 140.4.0 esr is able to.

Actual behavior

The TB app only shows "noname.eml" with a size of 0 B. Though tapping on the attachment and opening it e.g. in GMail (or downloading it) does show the contents of the eml file, but not the attachments contained inside them.

The TB app shows two noname.eml files as attachments, while desktop TB shows two eml files and all 4 attached PDF files. Also in desktop TB, above the forwarded emails, TB displays a "ForwardedMessage.eml"

Logs

k9mail-logs.txt

Start by reproducing the issue with the linked k9mail-logs.txt and an Outlook message containing forwarded emails. Compare the Android attachment display with the stated Thunderbird for Linux behavior; done means the nested forwarded message and its PDF attachments are displayed rather than empty noname.eml entries.