Why does the Laravel / Eloquent fresh function return an object, but call it the attribute return 0?

Question

My code has an address Modelin Eloquent, it looks like this:

Remarkably: all my models use uuid for the primary key, it is generated by a trigger in the MySQL database. This in itself works well.

<?php namespace App\Models;

    use Illuminate\Database\Eloquent\Model;

    class Address extends Model {    
        protected $table = 'Addresses';
        protected $fillable = ['uuid', 'zipCode', 'houseNumber'];
        protected $primaryKey = 'uuid';
        public $incrementing = false; //<- without this it returns 0, with it returns null
    }

In my controller, I create a function to create a new address, which gets its uuid from the trigger (as mentioned above). To pass this uuid, that is also a foreign key, I'm trying to call my userfresh();

<?php
public function store(Request $request) {
    $input = $request->all();
    try {
        $address = Address::create($input);
        // Call fresh to also get the trigger generated uuid primaryKey
        $address = $address->fresh(); //bug!!!
        //$address = Address::query()->where('zipCode', '=', $address->zipCode)->where('houseNumber', '=', $address->houseNumber)->first(); //works, but is not as nice
    }  catch (\exception $e) {
        $response['error'] = $e->getMessage();
        return response($response, 400);
    }
}

before rebooting (and getting my uuid), the object $addressis

object(App\Models\Address)#186 (23) {
  ["table":protected]=>
  string(9) "Addresses"
  ["fillable":protected]=>
  array(3) {
    [0]=>
    string(4) "uuid"
    [1]=>
    string(7) "zipCode"
    [2]=>
    string(11) "houseNumber"
  }
  ["primaryKey":protected]=>
  string(4) "uuid"
  ["incrementing"]=>
  bool(false)
  ["connection":protected]=>
  NULL
  ["keyType":protected]=>
  string(3) "int"
  ["perPage":protected]=>
  int(15)
  ["timestamps"]=>
  bool(true)
  ["attributes":protected]=>
  array(4) {
    ["zipCode"]=>
    string(6) "4651ZX"
    ["houseNumber"]=>
    string(2) "34"
    ["updated_at"]=>
    string(19) "2016-11-28 23:13:47"
    ["created_at"]=>
    string(19) "2016-11-28 23:13:47"
  }
  ["original":protected]=>
  array(4) {
    ["zipCode"]=>
    string(6) "4651ZX"
    ["houseNumber"]=>
    string(2) "34"
    ["updated_at"]=>
    string(19) "2016-11-28 23:13:47"
    ["created_at"]=>
    string(19) "2016-11-28 23:13:47"
  }
  ["relations":protected]=>
  array(0) {
  }
  ["hidden":protected]=>
  array(0) {
  }
  ["visible":protected]=>
  array(0) {
  }
  ["appends":protected]=>
  array(0) {
  }
  ["guarded":protected]=>
  array(1) {
    [0]=>
    string(1) "*"
  }
  ["dates":protected]=>
  array(0) {
  }
  ["dateFormat":protected]=>
  NULL
  ["casts":protected]=>
  array(0) {
  }
  ["touches":protected]=>
  array(0) {
  }
  ["observables":protected]=>
  array(0) {
  }
  ["with":protected]=>
  array(0) {
  }
  ["exists"]=>
  bool(true)
  ["wasRecentlyCreated"]=>
  bool(true)
}

If in my address model is $incrementing = false;defined, and I $address = $address->fresh(); now call the object $addressis equalNULL

$incrementing = false;, $address = $address->fresh(); $address

object(App\Models\Address)#195 (23) {
  ["table":protected]=>
  string(9) "Addresses"
  ["fillable":protected]=>
  array(3) {
    [0]=>
    string(4) "uuid"
    [1]=>
    string(7) "zipCode"
    [2]=>
    string(11) "houseNumber"
  }
  ["primaryKey":protected]=>
  string(4) "uuid"
  ["connection":protected]=>
  NULL
  ["keyType":protected]=>
  string(3) "int"
  ["perPage":protected]=>
  int(15)
  ["incrementing"]=>
  bool(true)
  ["timestamps"]=>
  bool(true)
  ["attributes":protected]=>
  array(5) {
    ["uuid"]=>
    string(36) "0e85ea0c-b5c0-11e6-9c20-002590f967ca"
    ["zipCode"]=>
    string(6) "4651ZX"
    ["houseNumber"]=>
    string(2) "34"
    ["updated_at"]=>
    string(19) "2016-11-28 23:11:56"
    ["created_at"]=>
    string(19) "2016-11-28 23:11:56"
  }
  ["original":protected]=>
  array(5) {
    ["uuid"]=>
    string(36) "0e85ea0c-b5c0-11e6-9c20-002590f967ca"
    ["zipCode"]=>
    string(6) "4651ZX"
    ["houseNumber"]=>
    string(2) "34"
    ["updated_at"]=>
    string(19) "2016-11-28 23:11:56"
    ["created_at"]=>
    string(19) "2016-11-28 23:11:56"
  }
  ["relations":protected]=>
  array(0) {
  }
  ["hidden":protected]=>
  array(0) {
  }
  ["visible":protected]=>
  array(0) {
  }
  ["appends":protected]=>
  array(0) {
  }
  ["guarded":protected]=>
  array(1) {
    [0]=>
    string(1) "*"
  }
  ["dates":protected]=>
  array(0) {
  }
  ["dateFormat":protected]=>
  NULL
  ["casts":protected]=>
  array(0) {
  }
  ["touches":protected]=>
  array(0) {
  }
  ["observables":protected]=>
  array(0) {
  }
  ["with":protected]=>
  array(0) {
  }
  ["exists"]=>
  bool(true)
  ["wasRecentlyCreated"]=>
  bool(false)
}

, !

$address['uuid'] $address->uuid, int(0) ( NULL)