An override was applied in the property set definition that is attached to the object. Property data formats control how units are edited and displayed. If you assign a type of unit other than the default in the property set definition, an override is applied to the property data format. Units specified in the property set definition controls what is stored in the drawing. The Extended Data tab of the Properties palette displays the units as defined in the property data format.
For example, with units specified as inches and unit format specified as Architectural in the property data format for Length–Long, when you select Length–Long for Format in the property set definition, Inches displays for Units by default. You can select any other type of unit that is identified for Length–Long (such as feet and millimeters). If you select Feet in place of Inches in the property set definition, and select a door with a manual property called HeightOverride, and enter 84 on the Extended Data tab, the value displays 7'-0''.