ESI shortcode & WordPress Twenty Twenty-Three Theme

When trying to create a shortcode with ESI in LiteSpeed using [esi shortcode] nothing is returned. LiteSpeed Enterprise is used, and ESI is enabled.

function this_is_a_test {
return ‘This is a test’;
}
add_shortcode(‘test_shortcode’, ‘this_is_a_test’);

[test_shortcode] returns This is a test.
[esi test_shortcode] returns nothing.

I read somewhere about a bug in “new” themes like 2023 and 2024. But as this was an old post, I assume this has to be fixed by now?