Suddenly plugin is malfunctioning

I’ve got YITH Infinite Scroll running on 4 pages of my website:
1) https://peerunschooling.net/discussions/
2) https://peerunschooling.net/video-submissions/
3) https://peerunschooling.net/audio-submissions/
4) https://peerunschooling.net/gallery/

As I remember things, there would be a button on the screen that would say “Load More” and upon clicking it, more content would load. I’m not sure when the change happened, but suddenly all the pages are acting very different.

On #1 and #4 there’s no more Infinite Scroll at all. On #2 and #3, the Infinite Scroll doesn’t use a button anymore, it just uses scrolling to trigger.

Any idea what’s gone wrong here?

The page I need help with: [log in to see the link]