That's exactly what I heard! Even after I got it wrong, I listened to it several more times. And I swear the audio is saying, "Cxu la persono estas banbona?" You can't expect people to get it right if the audio is wrong in the first place.
At least 4 of us, who were willing to admit it of course, heard "banbona", even after listening numerous times (in my case, waiting for a different "hearing" each time lololol). I thought that maybe it was a new word.