I am hosting a large training session where we use the Teams Rooms feature to encourage collaboration in small groups. When I allow Teams to automatically assign attendees to the rooms, fairly regularly I end up with a single attendee alone in a room even though other attendees are shown to be assigned to that room. The one attendee has a status of "In meeting". The other attendees do not. This example shows 5 attendees in Room 9 - only two of them were actually in attendance.
I assume Microsoft must use the actual attendee list to populate the room assignments (and not the meeting invite list) - but is it an attendee snapshot or is it real time? For example, if someone joined the meeting and later dropped, would they be assigned to a room? Or, for multi-session training, if they attended the prior session but not this one - would Teams still assign them?
Bottom line: where does the list of attendees used by Teams come from when automatically assigning Rooms?