It has nothing to do with "a riddle of logic". It's not NASA making confusing statements. It's the hype in the news about the statements made by a couple of scientists that have nothing to do with NASA that is confusing you.

As far as NASA, they admit that if the scientists' hypothetical planet "Tyche" does exits, it may be visible in the WISE data. But the hypothesis is not NASA's. There may be no planet "Tyche" there.