I am intrigued, why would the pitot heat fail because of CB activity.
The heaters don't fail. The pitots ice up, but the heater melts them usually within a minute. They get wet because of a storm at high altitude (usually the air is dry up there, but the storm pushes the moisture up), the plane then goes through very dry air, and the moisture ices up due rapid evaporation (dry enough to pull the heat away, causing the ice, but not enough to get rid of enough of the moisture to prevent the ice). Subtle changes in the shape of the pitot or changes in it's heater, may be the reason why one brand of pitot may work better than the other. There may be other scenarios for pitots with working heaters to ice up. That's just one I can think of. The heaters, in some cases, may cause the icing, because, when it's ultra cold, Ice particles act more like sand (ask arctic explorers), and don't stick together (sleds don't even slide), but the heaters may melt them enough to stick to one another. Sorry the explanation is a bit rambling, speculative, or down right inaccurate. The beer is kicking in.