Laravel model event does not fire - php

Question

I've made a custom trait in laravel 5.4 so when a pivot table is being ->sync(); it will fire an update event and then I will listen to that with an observer.
However it's not working the way I want.
In my app service provider:
Organisation::observe(OrganisationObserver::class);
There I've got this:
/**
* Listen to the Organisation updated event.
*
* #param Organisation $organisation
* #return void
*/
public function updated(Organisation $organisation)
{
dd('test');
$this->cache->tags(Organisation::class)->flush();
$this->cache->tags(Relation::class)->flush();
}
THis is the trait I use on the model:
<?php
namespace App\Deal\Custom;
trait BelongsToManyWithSyncEvent
{
/**
* Custom belongs to many because by default it does not observes
* changes on pivot tables. When a pivot table is changed return
* a custom belongs to many with sync cache clear class.
* Here we will clear the cache.
*
* #param $related
* #param null $table
* #param null $foreignKey
* #param null $relatedKey
* #param null $relation
* #return BelongsToManyWithSyncCacheClear
*/
public function belongsToMany($related, $table = null, $foreignKey = null, $relatedKey = null, $relation = null)
{
if (is_null($relation)) {
$relation = $this->guessBelongsToManyRelation();
}
$instance = $this->newRelatedInstance($related);
$foreignKey = $foreignKey ?: $this->getForeignKey();
$relatedKey = $relatedKey ?: $instance->getForeignKey();
if (is_null($table)) {
$table = $this->joiningTable($related);
}
return new BelongsToManyWithSyncCacheClear(
$instance->newQuery(), $this, $table, $foreignKey, $relatedKey, $relation
);
}
}
The BelongsToManyWithSyncCacheClear class looks like this:
<?php
namespace App\Deal\Custom;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Database\Eloquent\Concerns\HasEvents;
use Illuminate\Database\Eloquent\Relations\BelongsToMany;
class BelongsToManyWithSyncCacheClear extends BelongsToMany
{
use HasEvents;
/**
* BelongsToManyWithSyncEvents constructor.
*
* #param Builder $query
* #param Model $parent
* #param string $table
* #param string $foreignKey
* #param string $relatedKey
* #param null $relationName
*/
public function __construct(Builder $query, Model $parent, $table, $foreignKey, $relatedKey, $relationName = null)
{
parent::__construct($query, $parent, $table, $foreignKey, $relatedKey, $relationName);
}
/**
* When a pivot table is being synced,
* we will clear the cache.
*
* #param array|\Illuminate\Database\Eloquent\Collection|\Illuminate\Support\Collection $ids
* #param bool $detaching
* #return array
*/
public function sync($ids, $detaching = true)
{
$changes = parent::sync($ids, $detaching);
$this->fireModelEvent('updated', false);
return $changes;
}
}
Here I fire an updated event:
$this->fireModelEvent('updated', false);
But the dd('test'); in my OrganisationObserver is never triggered. What am I doing wrong here!?