The "Mark" property, when placing structural members, is not populating. When we place a new piece of steel we also try to give it a "Mark" number as part of the Structural Data.
If we immediately "Modify Structural Attributes" on the member, the mark field is blank. If after the steel is placed we add a "Mark" number the field is kept. Is there something that would cause this action?
The "Mark" property is derived from the Part definition. So if you look in Family/Part Editor under structural parts for Steel, are you able to edit that or add a Mark value? It is possible that the Parts are set to read-only.