The data-secondary-text does not display on the option in a mdb-select.

I've tried copying the example from the documentation and the mdb-select itself works.

<select class="md-form mdb-select initialized" searchable="Search here...">
    <option selected="selected" value="0" data-secondary-text="">Select an asset...</option>
    <option value="1" data-secondary-text="Dell · MS116-BK">00001 - Optical Mouse</option>
    <option value="2" data-secondary-text="Dell · Latitude 3500 · i5 8GB RAM">00002 - Laptop</option>
    <option value="3" data-secondary-text="BenQ · GL2450">00003 - 24" Monitor</option>
    <option value="4" data-secondary-text="Samsung · Tab 3">00004 - Tablet</option>
    <option value="5" data-secondary-text="Samsung · Tab 3">00005 - Tablet</option>
    <option value="6" data-secondary-text="Samsung · Tab 3">00006 - Tablet</option>
    <option value="7" data-secondary-text="">00007 - Patch Lead 0.5m</option>