Loading delay – Slides are stacked

I use this plugin with Elementor templates, so each slide is an individual section template build with Elementor.

I am getting a slight delay when the page loads and it appears the slides are stacked vertically down the page. Then it loads and they slide correctly.

Is there any way to avoid this delay – since it looks like a mistake?

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