Searchable seems not to work with 'relation.prop:group_concact'

Hello !

I have a little problem with the search function, I have a column Type with a ManyToMany relation (and so a pivot table). As mentioned in the documentation, I am able to retrieve the concatenated list of types with : 'types.title:group_concat'
This works perfectly and I can then process this list and display it as I want (here I split the list and process each element individually).

Anyway, my issue is related to the search, I did add the searchable() but unfortunately, it doesn't seem to work and I can't find the entries by typing the title of a type (I tried typing the id of a type, and I even tried typing a count to see if that was what was being search. But it doesn't do anything and this could be a problem, does anyone have an idea how to fix this problem? Did I make a mistake?

I thank you in advance

Column::callback('types.title:group_concat', function ($value) {
    $types = preg_split("/,+/", $value, 0);
    $result[] ='';
    foreach ($types as $i => $type) {
        if($i <= 2) {
            $result[] = "<span> " . $type . " </span>";
        } 
    }
    if(count($types) > 3) {
        $hiddenTypes = count($types) - 3;
        $result[] = "<span> +" . $hiddenTypes . " </span>";
    }
    return join('', $result);
})
->searchable()
->unsortable()
->label('Type'),

(Spans are normally stylized, here I removed their classes to improve readability)

Start with the documented types.title:group_concat syntax and the provided searchable() column definition. Trace how searchable relation and callback columns are turned into a search query, then check whether the related type title is included; done means searching by a type title returns the expected entries.