Cannot constraint rebar in geometry exported from dynamo

Hi, I have created simple geometry in Dynamo, then exported it to generic family type by ImportInstance.ByGeometry. The problem is, in project I cant add constraints to my rebar. It gives me warning:
“The current rebar component has no constraint. You can apply a new constraint by selecting a valid target.Rebar components are the geometrical references that define the bar set. For example, the shape segments or the host surface.”
Did I make mistake somewhere or imported geometry cannot host rebar in regular way?

Edit: I have also tried Form.ByGeometry from SpringNodes, without luck
Edit2: I attached family Culert.rfa (420 KB)