The duct/pipe has been modified to be in the opposite direction causing the connections to be invalid.

public static FailureDefinitionId DuctPipeOpositDirection { get; }

Public Shared ReadOnly Property DuctPipeOpositDirection As FailureDefinitionId
	Get

public:
static property FailureDefinitionId^ DuctPipeOpositDirection {
	FailureDefinitionId^ get ();
}