If I focus the inputs by clicking the label moves up correctly but if I use the tab key to move it doesn't work.

To reproduce you can test it on the contacts section or with this code:

<div class="row">

  <!--Grid column-->
  <div class="col-md-6">
    <div class="md-form">
      <input type="text" id="contact-name" class="form-control" [mdbValidate]="false" mdbInputDirective>
      <label for="contact-name" class="">Il tuo nome</label>
    </div>
  </div>
  <!--Grid column-->

  <!--Grid column-->
  <div class="col-md-6">
    <div class="md-form">
      <input type="text" id="contact-email" class="form-control" [mdbValidate]="false" mdbInputDirective>
      <label for="contact-email" class="">La tua email</label>
    </div>
  </div>
  <!--Grid column-->

</div>