Outlook for Mac not showing attachments in a separate window

When composing an email in Outlook, all added attachments are visible in the main interface. However, once I pop out the message into a separate window, the attachment section becomes blank, and I can no longer see the files I’ve attached.

Environment:

Microsoft Office for Mac
Version 16.103 (25110922)

OS: Tahoe 26.0.1

MacBook Pro 14 M4 Pro (Nov 2024)

In Main Interface:

In a Separate Window