If the subscription status is in error on CTM for the given room, that means we are no longer listening for new event notifications that occur on that room's calendar. Any new meeting events generated while the room is in subscription won't be received by CTM; once the subscription error clears Exchange won't send out a new notification as a result.
For the meeting scenario you describe above, you will most likely either have to:
a) Resync the room manually from CTM;
b) Reaccept the meeting from the room's calendar;
c) Have the scheduler open the meeting on their calendar and hit "Send Update" in order for the notification for the given room to be received by CTM, or
d) See if the nightly maintenance task (which resyncs the rooms calendars) picks up the meeting for the room.
HTH -
Tina
