You are using more than one dropdown, you should group each one within a container as a div
:
<div>
<button data-toggle="dropdown" class="btn btn-blue-grey btn-lg btn-group" mat-button>
Configurações <i class="fa fa-caret-down" aria-hidden="true"></i>
<br>
<i class="fa fa-cog mr-1" aria-hidden="true"></i>
</button>
<div class="dropdown-menu animated fadeIn" >
<a class="dropdown-item waves-effect" href="#">Cadastro de Operadores</a>
</div>
</div>
<div>
<button data-toggle="dropdown" class="btn btn-blue-grey btn-lg btn-group" mat-button>
Produtos <i class="fa fa-caret-down" aria-hidden="true"></i>
<br>
<i class="fa fa-cog mr-1" aria-hidden="true"></i>
</button>
<div class="dropdown-menu animated fadeIn">
<a class="dropdown-item" href="#">Tipo de Produtos</a>
<a class="dropdown-item" href="#">Produtos</a>
</div>
</div>
data-target
is used with modal, not with dropdown. Remove them from the buttons.
If you want the buttons side by side, use the class .btn-group
:
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js"></script><linkrel="stylesheet" type="text/css" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css">
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.11.0/umd/popper.min.js"integrity="sha384-b/U6ypiBEHpOf/4+1nzFpr53nxSS+GLCkfwBdFNTxtclqqenISfwAzpKaMNFNmj4" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script><divclass="btn-group">
<button data-toggle="dropdown" class="btn btn-blue-grey btn-lg btn-group" mat-button>
Configurações <i class="fa fa-caret-down" aria-hidden="true"></i>
<br>
<i class="fa fa-cog mr-1" aria-hidden="true"></i>
</button>
<div class="dropdown-menu animated fadeIn" >
<a class="dropdown-item waves-effect" href="#">Cadastro de Operadores</a>
</div>
</div>
<div class="btn-group">
<button data-toggle="dropdown" class="btn btn-blue-grey btn-lg btn-group" mat-button>
Produtos <i class="fa fa-caret-down" aria-hidden="true"></i>
<br>
<i class="fa fa-cog mr-1" aria-hidden="true"></i>
</button>
<div class="dropdown-menu animated fadeIn">
<a class="dropdown-item" href="#">Tipo de Produtos</a>
<a class="dropdown-item" href="#">Produtos</a>
</div>
</div>
Do not forget that the dropdown requires popper.js
.