Forwarded calendar invitation default to encrypted and can not be disabled

I was told that this outcome was by design, but I am not sure that it makes any sense.

I have MS Outlook for the Mac version 16.54. I have my Outlook configured to default to encrypting and signing my messages.

If I forward a Calendar invitation to someone, it will default to Encrypted and Signed.

This is where the expected behavior is different. I would expect that I can go into options and turn off Encrypt and Sign especially if I am sending to an external email address.

In reality, Outlook will allow me to turn of Signing only Encryption is ghosted out.

The work around for this is that every time I need to forward a meeting to an external email address (or even an internal mailing list that is not configured for an encrypted message) I have to...

Go into Outlook Preferences > Accounts > Advances > Security and disable “Encrypt outgoing messages”

Forward the message (If I wanted, I could turn off the signing under options).

Then go back into Outlook Preferences > Accounts > Advances > Security and enable “Encrypt outgoing messages”

This is not a practical work around or a good design.