shortcode lookup being weird -- explicitly calling RenderString seems to help?

layouts/_default/single.amp.html

@@ -196,7 +196,7 @@
         on <a class="date" href="{{ (.OutputFormats.Get "html").Permalink }}">{{ .Date.Format "January 2, 2006" }}</a>
       </p>
 
-      {{ .Content }}
+      {{ .Page.RenderString .Content }}
     </article>
 
     <footer>

layouts/_default/single.html

@@ -15,7 +15,7 @@
       </div>
     </div>
     <div id="content">
-      {{ .Content }}
+      {{ .Page.RenderString .Content }}
     </div>
   </article>
 </main>