Run is joining landing with riser, so notch configuration does not take effect. Try to set run as begin/end with tread to make a notch.
Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 26.2.0.0 (26.2.0.0)
Syntax
C#
public static FailureDefinitionId RunIsJoiningLandingWithRiserSoNotchDoesNotWorkWarning { get; }