Can't reverse eloquent relationships in Laravel

On my Laravel app, I'm currently working on users being able to "block" other users.

In my user models, I try to define the "blocked" relationships between users:

public function blockedOfMine() {
    return $this->belongsToMany('CommendMe\Models\User', 'blocked', 'user_id', 'blocked_id');
}

public function blockedBy() {
    return $this->belongsToMany('CommendMe\Models\User', 'blocked', 'blocked_id', 'user_id');
}

public function blocked() {
    return $this->blockedOfMine()->get();
}

public function blockedMe() {
    return $this->blockedBy()->get();
}

public function isBlocked(User $user) {
    return (bool) $this->blocked()->where('id', $user->id)->count();
}

public function hasBlockedMe(User $user) {
    return (bool) $this->blockedMe()->where('id', $user->id)->count();
}   

Basically, this model is only trying to figure out whether a user has blocked another user (function isBlocked) or whether a user has been blocked by another user (function hasBlockedMe).

Now, the first function works just fine, however the second one doesn't, despite them being completely the same:

if (Auth::user()->isBlocked($user)) {
   return redirect()->back()->with('info', 'You cannot message blocked users.');    
}
if (Auth::user()->hasBlockedMe($user)) {
   return redirect()->back()->with('info', 'This user has blocked communications with you.');   
}   

so if I try to message a user who is blocked, I get the message "You cannot message blocked users.", but the message goes through perfectly fine when I try to message a user who has blocked me.

What am I doing wrong?

via Felix Maxime