Last April, after toy tycoon Al Kahn purchased the former penthouse home of Ponzi schemer Bernard Madoff for $8 million at 133 East 64th Street, his wife, Patsy, told the New York Post that he “was worried about the [apartment’s] karma” — turns out, he may have had reason to be concerned. The duplex home between Lexington and Park avenues is still vacant, sources say, and a mysterious blaze may be to blame, according to the Post. Compounding the Kahns’ problems are purported marital problems and a disappointing collection of offers on their former home, a 62nd-floor unit at the Time Warner Center in Columbus Circle. While they have nailed down a buyer, the couple has been offered around $20 million — a far cry from the unit’s $33 million asking price when it first hit the market last year. [Post]