Laravel 5.2 relationships: Trying to get property of non-object - laravel-5

Question

I have two models: Term and Post.
The Term model represents both categories and tags.
A post can belong only to a category and it can have many tags (I use the same db table for categories and tags).
class Term extends Model
{
protected $table = 'mydb_terms';
public $timestamps = true;
public function getRouteKeyName() {
return 'slug';
}
public function posts(){
return $this -> hasMany('Post');
}
}
class Post extends Model
{
use SoftDeletes;
protected $table = 'mydb_posts';
public $timestamps = true;
public function category(){
return $this -> belongsTo('Term','mydb_posts_terms', 'post_id', 'term_id')
-> withPivot('order') -> withTimestamps() -> where('type','category');
}
public function tags(){
return $this -> hasMany('Term') -> where('type','tag');
}
}
In the CategoryController I have:
class CategoryController extends Controller
{
public function getPostsOfCategory($id)
{
$posts = Term::find($id)->posts->get();
}
public function getPostsOfAllCategories()
{
//
}
}
When I try to retrieve the posts of category event with slug event (in the db the category and one post in it exist, and also the corresponding row in mydb_posts_terms) I obtain
Trying to get property of non-object
EDIT
I tried both $posts = Term::find($id)->posts()->get(); by obtaining Call to a member function and $posts = Term::find($id)->posts; by obtaining the same Trying to get property of non-object.
In the db I have:
Table mydb_terms:
| id | name | slug | type | created_at | updated_at
| 1 | event | event | category | 2016-07-01 18:00:00| 2016-07-01 18:00:00
Table mydb_posts:
| id | title | content | created_at | updated_at
| 1 | A title | a content | 2016-07-04 17:20:12| 2016-07-04 17:20:12
Table mydb_posts_terms:
| post_id | term_id | order | created_at | updated_at
| 1 | 1 | 0 | 2016-07-06 14:13:43| 2016-07-06 14:13:43