I didn’t fix it but found a workaround. I believe it was either to turn off “Enable image preloader for all pages?” in the theme or to disable lazy loader in the slider. I have both off now so I can’t recall which one was the solution.
Thanks for RC2. I would just like to note that Line 69 still requires the ceil function or else the last page won’t show. i.e.:
‘total’ ► ceil($total_files/$items),