I don't use fastener systems but it seems apparent that with the angled face the implied axis is not normal to the face. Perhaps, if possible, select a different mate sequence without trying to align the angled face with the fastener face. Maybe using coaxial with connect or some such combination.
Then that would mean the washers would not be normal to the bolt and nut. Therefore you'd have to use different mates. It can be done but, aside from model isssues, mechanically is it ok to have the bolt head and nut not normal to the washers or do you need beveled washers?