This sounds like a problem with the GroupWise command that reports if you are in plain text or HTML mode. I recall some issues with this token with some earlier GroupWise clients.
I need to know the exact release of the GroupWise client you have. Start GroupWise, then from the main menu select Help | About Formativ. When the about box appears select the configuration tab. Press the ‘copy to clipboard’ button, then paste the contents of the clipboar into a message addressed to firstname.lastname@example.org and we’ll take it from there.