ZOOM meeting on screen with attendee on laptop - interference

At a recent meeting I normally host, a guest had some docs to share separate from the docs I was sharing.  This was last minute.  The guest took control as host or just posted some docs (I don't know how or which), showed the docs from the laptop the guest brought.  Once the docs were shown -- the meeting was still going on -- i tried to share my own docs to the assembled in person and zoom guests.  The entire polycom screen turned blue and although we could hear the zoom attendees, for the next several hours the meeting ran, with the gallery and my docs on the guests laptop and NOT on the full screen for the in person attendees.  Therefore at the meeting's conclusion, no one in the meeting room saw the docs.  They also complained of sound issues.  What happened?  I think I know but need clarification.  Thanks.