Arrows get stuck

Hi.

Thanks for the great plugin.

I have a problem where the arrows get “stuck” (e.g. they are not clickable anymore) after being clicked a few times.

Here is the URL:

http://www.thejupiterdrawingroom.com/sanctum-sanctorum/

Is there any solution for this or insight into what might be causing the problem?

Thank you.
Bardin

https://wordpress.org/plugins/wp-booklet/