VERSION: 2011 (update 1)
PROBLEM:
Room objects don't extend to walls around a space.
POSSIBLE CAUSE:
Adjacent walls (including curtain walls) run through the space. These walls have had their profile edited, but the underlying wall actually cuts through the space.
SOLUTION 1:
Remake the offending walls, ensuring the underlying wall doesn't cut through the space.
SOLUTION 2:
Turn off Room Bounding in the offending walls. You will need to check if this effects other rooms.
HOW TO AVOID:
Problem is mostly likely to occur when making facades. Make sure facade walls don't extend into the building.
If this is not possible, make offending walls (including curtain walls) non-Room Bounding.
Revit now uses linked files to define room boundaries, so don't assume the problem won't occur just because the facade is in a linked file.