Shortcode assets not loaded in modular item

I call shortcode-owl-carousel plugin in a modular subpage content. But assets needed by this plugin are not loaded (no JS and no CSS)
When I move the exact same content to the parent modular page it works!
Also it works with the same code in a page content (outside a modular).

I tried with another plugin, shortcode-ui and I get the same behaviour...

I use Grav v1.6.7

Thanks for your help