Does the material in your Architectural Columns look strange? Chances are, they automatically JOINED to a wall.
Architectural Column families will adopt the material of the wall that they are joined to. If you don’t want that material, you can just UNJOIN the column from the wall and it will revert back to the material you gave it when you created it.
If you can plan ahead, you can edit it and uncheck the AUTOMATICALLY JOINS GEOMETRY TO WALLS parameter in the Family Category and Parameters before you place it.