A frequent point of confusion for anyone coordinating architecture with MEP in Revit: Rooms and Spaces are two separate element types that can occupy the exact same physical volume but belong to different disciplines and different Revit categories entirely. Architects place and schedule Rooms; MEP engineers place Spaces (used for HVAC load calculations and energy analysis) - and the two do not automatically stay in sync with each other.

Best practice is usually to let Spaces derive their boundaries directly from the architectural model's Rooms wherever possible, and to re-check that link whenever the architectural layout changes - otherwise an MEP team can end up doing load calculations against room boundaries that no longer match the actual design.