There is an error that causes a popup not to open on click

There is an error that causes a popup not to open on click if two popups are on the same page. On this site my client has two links which should open two different different popups on click.

If I click the second link it will sometimes open first time and not other times but the second link will fail on repeated clicks every time after the first.
The JS does not preventDefault() after the first click.

Basically: The first link will continue to open a popup when re-clicked but the second link will not.
I hope this makes some form of sense

Try clicking the large images at the end of the home page to test.

Thanks

kieran