I had one go bad this year too. I don't think it was the LE's fault, nor do i believe it was mine. I was using banks of floodlights in outdoor light stakes pointing straight up under the house, and rain got in. I called the company that makes the holders, and they told me that they can NOT be used pointing straight up, or they won't be waterproof (even though it said this no where in the instructions).
Luckly I had some spare channels. I'm assuming this can be fixed after the season? Since a bunch of us seem to be having this problem, can someone post instructions on the easiest way to unsolder and replace a triac?