Didn't hear the Leo Burnett part, but I dinstinctly heard "4katd", without prompting or prior knowledge that is what I was listening for.

Looking further, it appears as if the nerds who are "in the know" about this incident believe it is legitimate and intentional, with TVTropes even going so far as to claim that 4kids admitted to it. I have not yet been able to locate an original source, whether from the voice actor himself or from some other employee, so I cannot confirm the internet hive-mind's claims of premeditated intent - but it *could* be legit?

Found something:

https://www.youtube.com/watch?v=ZYkZBDkMf04

Can't verify what the actual question was, and it is possible Mr Stuart was answering in jest - but it's a source, and it does corroborate the rumor.

Here's a rip of the episode someone posted on Daily Motion back in 2013.

http://www.dailymotion.com/video/x177nph_j03-130-the-whistle-s top_fun

It's on a channel from a person who just uploaded a bunch of plain old unedited Pokemon episodes. The backmasking is indeed there. Then there's the video of James's voice actor responding to it.

https://www.youtube.com/watch?v=ZYkZBDkMf04

So yes, it is unarguably legit.

Someone first discovered it back in 2007, and apparently knowledge of it became so widespread over the years that on the DVDs set featuring this episode that got released last year they removed the backmasking and replaced it with generic screaming.

para ti