I heard the same thing. Seems like I did some looking into since I had no idea what it was and this is what I found.
"On June 24, 2004, John Shulock called such a balk on the Braves' Greg Maddux when he pitched while catcher Fernando Lunar's foot was out of the box. Bobby Cox argued the call and was ejected. The night before, Brewers' manager Davey Lopes had asked the umpires to enforce the rule against the Braves' catcher Javy Lopez, who was setting up far outside the box. This appears to be the only time this balk has been called in decades.
Major League crew chief Tim McClelland has written "As a matter of fact, I have never seen it called, it's one of those things you just kind of let slide."
Apparently it doesnt get called in MLB, but it does in NKAC. The guy has issues.....