its hard to say.... I don't see how the filter and pipe could be getting wet without a source of water. My guess is that the water you are seeing is from the melted snow on the ground or perhaps the snow on your truck, if any.
The only other way that the pipe could be getting wet is condensation. Which, again, I don't see happening. The air in the pipe would have to be much cooler than the engine compartment, which it is due to winter/snow. At the same time, I think the heat from the compartment would evaporate any water too quickly to build up.
Anyway, It is one of the two reasons above. Snow/water from the road or condensation. Neither should be harmful to the performance, I wouldn't think.
Hope that helps.