Screen Share in Tile Only

Hello, all. We’ve seen a new problem crop up. During a relatively small conference (~6 attendees) most of the participants could see the shared screen in their normal viewing window but two could only see the screen share in the tile of the user doing the sharing. Even clicking on the tile did not bring it into the main view. I have never experienced this so I can only go by what they told me but it was more than one person.
Has anyone else seen this? If so, is there a way to get them back to main viewer viewing of the shared screen? Thanks.