NASA's Voyager Found a 30k-50k Kelvin "Wall" at the Edge of Solar System

"While not a hard edge, or a "wall" as it has sometimes been called, here both spacecraft measured temperatures of 30,000-50,000 kelvin (54,000-90,000 degrees Fahrenheit), which is why it is sometimes also referred to as a "wall of fire". The craft survived the wall as, though the particles they measured were extremely energetic, the chances of collision in this particle-sparse region of space are so low that not enough heat could be transferred to the duo."

Is there a chance this is an instrument error? Seems a strange phenomenon.