follow on to 526 (#528)

index.html

@@ -16842,7 +16842,7 @@ <h4>Substantive changes since moving to the Web Application Working Group (forme
     <section class="appendix informative" id="acknowledgements">
       <h3>Acknowledgments</h3>
       <p>The following people contributed to the development of this document.</p>
-      <section class="section" id="ack_group"> <!-- left in place to ensure deep links to ID remain functional -->
+      <div class="section" id="ack_group"> <!-- left in place to ensure deep links to ID remain functional -->
         <ul id="gh-contributors"></ul>
     			<!-- list of contributors will appear here,
 					 along with link to their GitHub profiles -->
@@ -16851,7 +16851,7 @@ <h3>Acknowledgments</h3>
           Add listing of individuals who have providing meaningful
           contributions through commenting that have impacted the specification.
         -->
-      </section>
+      </div>
       <div data-include="https://rawgit.com/w3c/aria/master/common/acknowledgements/funders.html" data-include-replace="true"></div>
     </section>
   </section>