swipeThreshold set to 50 px, yet takes a very long swipe to work

The swipeThreshold:50 in the js is 50 pixels, and yet you have to swipe nearly all the way across on my device (Android) to get to the next slide. If you do a shorter swipe, the image just bounces.

This seems odd, since the threshold is so small. What is causing this behavior? What setting can I change?

Otherwise, an awesome plugin, great solution for mobile browsers to work with NextGen.

https://wordpress.org/plugins/photoswipe-for-nextgen-gallery/