Thunderbird links open in a new, clean Edge profile instead of my Default profile

I am experiencing an issue where clicking links inside Thunderbird emails forces Microsoft Edge to launch a completely brand new window with a blank profile (no extensions, default settings). It does not open as a new tab in my active window. My environment details: • OS: Windows 11 (Version 25H2) • Default Browser: Microsoft Edge (Only one profile exists under edge://settings/profiles, no Workspaces used). • Thunderbird version: Latest stable release. When Thunderbird passes the HTTP/HTTPS link to Windows, Edge seems to ignore the standard "Default" user data directory profile and launches a temporary or guest-like profile container instead. Is this a known bug in how Thunderbird handles external URI handlers, or is it an Edge registry/default app assignment issue? Any help or workaround config settings would be appreciated. Thank you!