You have set the stair's multistory top level to None, and Revit will remove this parameter, if you want to create a multistory stair, please use Create Multistory Stair feature.

Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 17.0.0.0 (17.0.1090.0)

Syntax

C#
`public static FailureDefinitionId MultistoryStairsHideTopLevelParameter { get; }`

Visual Basic
`Public Shared ReadOnly Property MultistoryStairsHideTopLevelParameter As FailureDefinitionId Get`

Visual C++
`public: static property FailureDefinitionId^ MultistoryStairsHideTopLevelParameter { FailureDefinitionId^ get (); }`

MultistoryStairsHideTopLevelParameter Property

Syntax

See Also

Put AI to work inside Revit.