same issue here. After an alternator locked up, I replaced it, using the old belt that was only a month old. It had an irritating chirp-chirp-chirp that I attributed to a glazed spot on the belt. Replaced the new belt with another new belt and it was perfect for a few hundred miles.

Tensioner is good, so I'm going to try another belt - not the $8.95 Autozone belt thats on it now