this is a SP Pagebuilder issue, not from Scroll To CK ...
Check the html code that is rendered, the css class is not applied on the link ! (but on the parent div)
Code:
<div class="sppb-addon sppb-addon-header scrollTo sppb-text-center"><a href="#guard-your-network"><h2 class="sppb-addon-title"></h2><h2 class="sppb-addon-title"><span class="sp-inline-editable-element" data-id="1545390300727" data-fieldname="title" contenteditable="true"><h3 class="sppb-addon-title"><span class="sp-inline-editable-element" data-id="1545388520991" data-fieldname="title" contenteditable="true">Guard your Network </span></h3></span></h2></a></div>
