Shortcode not displaying

I'm using Metabox Custom Fields to add fields to a Metabox custom post type, which in turn is used to display markers and popups on a leaflet.js map.

When editing custom posts, admin users should be able to either add some free text, or paste a shortcode that will display the contents of that shortcode in the map popup.

The shortcode just holds a chunk of predefined text, edited in a third party content blocks WP plugin. The text can then be edit once > change in multiple map markers.

The custom field that the shortcode is added to is location_content_shortcode.

It's called in my list.js file like this:

var popupContentShortcode = '';
        if (location.location_content_shortcode) {
            popupContentShortcode = '<p>' + location.location_content_shortcode + '</p>';
        }

But on the website frontend, just the shortcode shows - [ls_content_block slug="tier-1"]

Any idea how I can fix this?