I've got it working.  A little tweak to the example accordion code from the MDB website is required.  Just move the data-parent="#accordionEx" from the anchor of the card header to the wrapper of the card body and it works.  Final code (which needs fixing on the MDB website) as follows.  Hope it helps somebody!  :-) <!--Accordion wrapper--> <div class="accordion" id="accordionEx" role="tablist" aria-multiselectable="true"> <!-- Accordion card --> <div class="card"> <!-- Card header --> <div class="card-header" role="tab" id="headingOne"> <a data-toggle="collapse" href="#collapseOne" aria-expanded="true" aria-controls="collapseOne"> <h5 class="mb-0"> Collapsible Group Item #1 <i class="fa fa-angle-down rotate-icon"></i> </h5> </a> </div> <!-- Card body --> <div id="collapseOne" class="collapse show" role="tabpanel" aria-labelledby="headingOne" data-parent="#accordionEx"> <div class="card-body"> Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS. </div> </div> </div> <!-- Accordion card --> <!-- Accordion card --> <div class="card"> <!-- Card header --> <div class="card-header" role="tab" id="headingTwo"> <a class="collapsed" data-toggle="collapse" href="#collapseTwo" aria-expanded="false" aria-controls="collapseTwo"> <h5 class="mb-0"> Collapsible Group Item #2 <i class="fa fa-angle-down rotate-icon"></i> </h5> </a> </div> <!-- Card body --> <div id="collapseTwo" class="collapse" role="tabpanel" aria-labelledby="headingTwo" data-parent="#accordionEx"> <div class="card-body"> Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS. </div> </div> </div> <!-- Accordion card --> <!-- Accordion card --> <div class="card"> <!-- Card header --> <div class="card-header" role="tab" id="headingThree"> <a class="collapsed" data-toggle="collapse" href="#collapseThree" aria-expanded="false" aria-controls="collapseThree"> <h5 class="mb-0"> Collapsible Group Item #3 <i class="fa fa-angle-down rotate-icon"></i> </h5> </a> </div> <!-- Card body --> <div id="collapseThree" class="collapse" role="tabpanel" aria-labelledby="headingThree" data-parent="#accordionEx"> <div class="card-body"> Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS. </div> </div> </div> <!-- Accordion card --> </div> <!--/.Accordion wrapper-->  

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