Bitcoinjs-lib Wallet WIF error

bitcoinjs-wif-error.js

var Wallet = require('./src/wallet.js');

var i = 0;
for(i = 0; i<5000; i++){
	generateAddresses(function(pub,priv){
		if(priv[0] == '5'){
			console.log('ERROR');
			console.log(pub);
			console.log(priv);
		}
	});
}

function generateAddresses(cb) {
	var wallet = new Wallet();
	wallet.newMasterKey();
	pub = wallet.generateAddress();
	//console.log(pub);
	//console.log(wallet);

	var priv = wallet.getPrivateKeyForAddress(pub);
	priv = priv.toWif();
	cb(pub, priv);
}