I, by far think that GE makes the absolute best halogen PAR today. I don't think there is anything wrong with your system or the lamp. I think it's your connectors at the lamp. I would cut back a couple of inches as perhaps the connections have probably heated up and caused damage to the wire internally. Replace all of those inexpensive connectors but make sure you apply contact grease to them before you install them. Another thing I have to through out there and it might sound like Duh, but just encase you don't know the lock washer goes on top of the connector between the screw head and the connector.
Business Developing Rep/TX Lighting