A little bit late but I hope this helps someone with the same issue.
On the file: wp-content/plugins/smooth-accordion/assets/js/smoothaccordion.js you can comment out (or delete, but it’s not recommendable) lines 184 to 192:
if(S.initial instanceof Array){
for(var i=0 ;i<S.initial.length; i++){
$contents.eq(S.initial[i]).show();
open(S.initial[i]);
}
} else {
$contents.eq(S.initial).show();
open(S.initial);
}