Mobile Menu - 100% width not working on menu toggle?

Hi guys

Having a strange issue with the mobile menu on my site, for some reason the CSS class for the toggled state isn't loading:

.main-navigation.toggled .main-nav li {
    width: 100%;
    text-align: left;
}

It should look like:

But it's looking like:

I do have WP Rocket installed but have removed all the JS optimisation, and cleared the cache. The strange thing is the mobile menu was working perfectly before, with JS optimisation options in place - so not sure if something else might have caused it to break.

The only other thing I've changed was switching from Google Fonts to self-hosted variable fonts (.woff2).

Thanks
Greg