[Smush Pro] Issues with lazy load on migrated site

I have an odd issue on the site I migrated here: although images do have the expected lazyload classes on them in source code, they appear to not be lazy loaded.

There is no other lazy load enabled in any other optimization plugin or the theme.

The functionality is working on the source site as expected with WP-Rocket, but appears to be having a bit of difficulty on this migrated site.

Can you please have a look?