Looking at the page, there are many HTML errors. Load the page in Chrome, hit the F12 key and then click the Console tab.
Most of the errors seem to occur no matter the page on your site. My first suggestion would be to resolve those. They appear to be caused by the login and registration forms being added to every page but set so they do not display.
Another error seems to be caused by the CDN, preventing the some fonts from being loaded.
These shouldn’t cause the issue you are experiencing, but it would be a good to eliminate those as the cause.
There is one error that will definitely break Form. It is the one that says “Uncaught TypeError: Cannot read property ‘length’ of undefined”.
It is difficult to tell why the error is occuring due to the Hummingbird cache and the CDN. Can you disable Hummingbird temporarily?