Yea based on that picture of the raw output looks like it is LED by the weak perfect oval output. A little rain I would not think would do it unless it was near completely submerged and the driver was soaked, shorted and bypassed getting the full load passed from the cells to the diode. Maybe a back reflection that could take it out. Sorry to hear that. If you plan on using the driver again I would check it on a test load first to make sure it is regulating properly still.