Watermarks don’t show up on Chrome or Edge browsers

I’ve set up the plugin, and everything works perfectly fine on Firefox and Safari browsers. However, the watermarks do not appear in Chrome or Edge browsers. If I clear the browser cache and reload the page in Chrome, I can get the watermark to appear … but only temporarily. When I leave the page and revisit it, the watermark disappears again.

Any help would be greatly appreciated. I love the plugin, but I need it to work on all browsers.

Thanks very much!

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