As with models that are imported or linked from AutoCAD Architecture, there are special behaviors exhibited with materials assigned to linked Revit objects. The behavior is controlled by the Propagate Materials To Instances.

When applying materials to a linked drawing in 3ds Max, family and type plays an important role in material management. Assigning a material to any component of any linked Revit object is equivalent to assigning the same material to every instance of that component in every object with the same family and type throughout your scene.

As an example, say you have multiple instances of a Doors <Single-Flush : 34” x 80”> door in your drawing, which consists of three components: two Frame/Mullion components representing the inside and outside trim and a Panel component. If you assign a material to one Panel component anywhere in your 3ds Max scene, all the Panels for all the Doors of that family and type throughout the scene will receive the new material.

If you want to keep materials from propagating between instances in your scene, turn off the Propagate Materials To Instances from the Material Editor's Options menu.