Multiple [Room] are in the same enclosed region. The correct area and perimeter will be assigned to one [Room] and the others will display "Redundant [Room]." You should separate the regions, delete the extra [Room], or move them into different regions.
Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 26.3.0.0 (26.3.0.0)
Syntax
C#
public static FailureDefinitionId RoomsInSameRegionSpaces { get; }