BelongsToMany Field Not Working on Create/Edit Forms

Environment

Laravel Version: ^11.9
Nova Version: 4.33.3
PHP Version: 8.2.12
Operating System and Version: Windows 11

Issue Description

I'm developing an education course website using Laravel Nova. I'm trying to implement a feature in my CourseSession resource that allows an admin to assign multiple beneficiaries (students) to a session at once. However, the current implementation is not working as expected on any view.

Current Behavior

Create Form: Unable to assign multiple beneficiaries when creating a new CourseSession and it's not even showing there.
Edit Form: Unable to assign or modify multiple beneficiaries when editing an existing CourseSession.
Detail View: I can see a table of beneficiaries and add them, but only one at a time and that expected.

Expected Behavior

On views (create, and edit):

There should be a field where the admin can select multiple beneficiaries at once.
When the form is submitted, it should create multiple entries in the beneficiary_session pivot table, one for each selected beneficiary.
The interface should allow for easy selection of multiple beneficiaries without having to add them one by one.

Current Database Structure

course_sessions table
beneficiaries table
beneficiary_session pivot table

Current Implementation

Here's my current implementation in the CourseSession Nova resource:

<?php

namespace App\Nova;

use Laravel\Nova\Fields\ID;
use Laravel\Nova\Fields\BelongsTo;
use Laravel\Nova\Fields\BelongsToMany;
use Laravel\Nova\Http\Requests\NovaRequest;

class CourseSession extends Resource
{
    public static $model = \App\Models\CourseSession::class;

    public function fields(NovaRequest $request)
    {
        return [
            ID::make()->sortable(),

            BelongsTo::make('Course'),

            // Other fields for CourseSession...

            BelongsToMany::make('Beneficiaries')
                ->searchable() // I don't care at the moment about the filter, I just need  the BelongsToMany to work
        ];
    }
}

And here are the relevant parts of my models:

// App\Models\CourseSession.php
class CourseSession extends Model
{
    public function course()
    {
        return $this->belongsTo(Course::class);
    }

    public function beneficiaries()
    {
        return $this->belongsToMany(Beneficiary::class, 'beneficiary_session'));
    }
}

// App\Models\Beneficiary.php
class Beneficiary extends Model
{
    public function courses()
    {
        return $this->belongsToMany(Course::class);
    }

    public function sessions()
    {
        return $this->belongsToMany(CourseSession::class, 'beneficiary_session');
    }
}

// App\Models\Course.php
class Course extends Model
{
    public function sessions()
    {
        return $this->hasMany(CourseSession::class);
    }

    public function beneficiaries()
    {
        return $this->belongsToMany(Beneficiary::class);
    }
}

The Problem

The multi-select functionality for beneficiaries is not working as expected on any view:

On the create form, I'm unable to select and assign multiple beneficiaries to a new CourseSession.
On the edit form, I can't modify multiple assigned beneficiaries or add multiple new ones to an existing CourseSession.

Questions

How can I modify my BelongsToMany field to allow multiple selections on all views (create, and edit)?
Is there a specific Nova field or configuration I should be using to enable bulk assignment of beneficiaries instead of this?
Are there any known issues or limitations with BelongsToMany fields in Nova that could be preventing multi-select functionality?

Any help or guidance would be greatly appreciated. Thank you!

laravel / nova-issues