The specification states (emphasis mine):
The organization that should be contacted for action under the terms of the warranty. Note that the role of the organization (manufacturer, supplier, installer etc.) is determined by the IfcActorRole attribute of IfcOrganization.
Firstly, the attribute is Roles, not IfcActorRole. Secondly, can it be confirmed that the “foreign key” that relates this property to is Name and not Identification? If so, this should be more explicit in the pset template definition.