Help troubleshooting the WP Properties Responsive Slideshow plugin

Somehow in the process of making some updates to my site, the responsive slideshow plugin broke, and I can’t tell why.

example (the slideshow widget is placed below the PDF flyer button): https://www.montanagrasslands.com/properties/20-irrigated-worden-mt/

The browser console is returning this error:swiper.min.js:12 Uncaught TypeError: Cannot read property ‘el’ of undefined
at h.render (swiper.min.js:12)
at h.snapGridLengthChange (swiper.min.js:12)
at swiper.min.js:12
at Array.forEach (<anonymous>)
at swiper.min.js:12
at Array.forEach (<anonymous>)
at h.s.emit (swiper.min.js:12)
at h.updateSlides (swiper.min.js:12)
at h.init (swiper.min.js:12)
at new h (swiper.min.js:12)

I’ve made three notable changes around the time this started:
1) I added some new seo and speed management tools. I have those all disabled again, cleared the site cache and my browser cache, but it didn’t fix the slideshow. They are still disabled.
2) I added https to the main site URL in WordPress’ general settings, which I reverted back to non-encrypted URLs and the plugin still won’t work.
3) I clicked the option to disable Fancybox in the WP Properties settings to see what it affected, but I unchecked it and re-saved settings right away. It’s still unchecked, and it was after this that I discovered the slideshow was broken, so I’m not sure if it’s related at all.

Any tips on what I should look into next?

Thank you!

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