As soon as an encrypted or signed email is opened in Outlook 365 64 bit (Version 2307 Build 16.0.16626.20170), using a 365 mailbox, the same email becomes unreadable in other clients (Thunderbird/K9 Mail), email is blank with the following attachment "GpgOL_MIME_structure.txt".
Sent emails opened in Outlook, become unreadable when opened from the sent folder in Thunderbird.
If the "alternative solutions" in the debug section of GpgOL are enabled the issue is solved (but only for the inbox, not for the sent emails).
We need a solution since there is no GPG plugin for other clients (there is no issue if we exclude Outlook and GpgOL from the equation, but we need Outlook to work correctly).
GPG4Win version: 4.2.0
GpgOL version: 2.5.8