Alternator and voltage regulator question

Any idea why a new 1 wire alternator would crap out the voltage regulator after only a month? I got one in from summit and installed it. I haven't been driving it that much. I was out driving and tinkering with tuning in my carburetor and it started charging 18-20 volts all of a sudden. So, I limped it home and called summit. The guy said he didn't have a problem exchanging it. But my question is what would possibly make a voltage regulator go out and what all should I check??