Laravel User ResourceController cannot update current User

I am using a resource controller UserController, with routes defined like:

Route::group([
    'middleware' => 'can:admin-user',
    'prefix' => 'admin',
], function(){
    Route::resource('user', 'Admin\UserController');
});

And an update function defined (by Laravel make) like:

public function update(Request $request, User $user)
{
    $validator = Validator::make($request->all(), [
        'email' => [
            'required',
            'string',
            'email',
            'max:255',
            Rule::unique('users')->ignore($user->id)
        ],
        'password' => ['sometimes', 'string', 'min:6'],
        'role' => ['sometimes', 'array'],
        'role.*' => ['sometimes', Rule::in(Role::all()->pluck('id')->toArray())],
        'permission' => ['sometimes', 'array'],
        'permission.*' => ['sometimes', Rule::in(Permission::all()->pluck('id')->toArray())],
    ]);

    if ($validator->fails()) {
        return redirect()
            ->route('user.edit', ['user' => $user])
            ->withErrors($validator)
            ->withInput();
    }

    $data = $validator->validated();
    foreach ($data as $k => $v) {
        if ($k === 'password') {
            $user->password = Hash::make($data['password']);
        } elseif($k === 'role') {
            $user->roles()->sync($v);
        }elseif($k === 'permission'){
            $user->permissions()->sync($v);
        } else {
            $user->$k = $v;
        }
    }
    $user->save();

    Flash::success(__('User updated'));

    return redirect()
        ->route('user.edit', ['user' => $user]);
}

If I edit any user except the one logged in it works just fine, but if I edit the current user it logs me out.

Where it breaks, specifically, is changing any of the User model attributes, if I just save the user without changing email or password it works, or if I just sync relations it works (so it is only a dirty model that causes it).

Weirdly, I have another action that works if I go on $request->user().

I have tied to find out why but haven't got far (Laravel noob).

Why is this?

via Chebli Mohamed