Duckpunches this bug in YUI 3.2.0PR1: http://yuilibrary.com/projects/yui3/ticket/2529123

gistfile1.js

Y.HistoryHTML5.prototype._init = function (config) {
    Y.on('popstate', this._onPopState, Y.config.win, this);

    config = this._config = config || {};

    if (config && config['enableSessionFallback'] && YUI.Env.windowLoaded) {
        this._loadSessionState();
    }

    Y.HistoryHTML5.superclass._init.apply(this, arguments);
};