Stage manager & Outlook = fail?

In testing Stage manager, I've noticed what appears to be a bug. If you have Outlook open (I have 16.66.1), and have a new email message open with a "new window", it locks up stage manager. It will not let you switch to that "stage" with the new email window open. Anyone else notice this? If you click the Outlook icon on the dock, Outlook and that stage will come back... strange!