WTF! ANYONE ELSE HEARD IT TOO?!
During the time Tobio did his performance (In the Japanese version of this episode), there was instrumental "Nanairo Achi" already playing! The fact is, when this episode was out, the ending was still "Can You Name All the Pokémon? BW." not Nanairo Achi. If you will listen closely to the part where Tobio says "Over the Rainbow" during their performance near the end, in the Japanese version, you can hear it playing! (instrumental version).
During the time Tobio did his performance (In the Japanese version of this episode), there was instrumental "Nanairo Achi" already playing! The fact is, when this episode was out, the ending was still "Can You Name All the Pokémon? BW." not Nanairo Achi. If you will listen closely to the part where Tobio says "Over the Rainbow" during their performance near the end, in the Japanese version, you can hear it playing! (instrumental version).