Expected behavior Material dropdown to be dropping down with an animation

Actual behavior Drop down has no animation just like mdb default (free) version

Resources (screenshots, code snippets etc.)

<!--Dropdown primary-->
<div class="dropdown">

  <!--Trigger-->
  <a class="btn btn-primary dropdown-toggle" type="button" id="dropdownMenu2" data-toggle="dropdown"
    aria-haspopup="true" aria-expanded="false">Material dropdown</a>


  <!--Menu-->
  <div class="dropdown-menu dropdown-primary">
    <a class="dropdown-item" href="#">Action</a>
    <a class="dropdown-item" href="#">Another action</a>
    <a class="dropdown-item" href="#">Something else here</a>
    <a class="dropdown-item" href="#">Something else here</a>
  </div>
</div>