Add issue about adjusting timeline time values

Author: birtles

web-animations/index.html

@@ -8105,8 +8105,13 @@ <h2>Interaction with page display</h2>
         unloaded and traversed,
         are encouraged to apply consistent handling to documents containing Web
         Animations content.
-        If provided, this behavior SHOULD be achieved by adjusting the time
-        values of any <a>timelines</a> bound to the <a>global clock</a>.
+        If provided, this behavior SHOULD be achieved by adjusting the <a>time
+        values</a> of any <a>timelines</a> bound to the <a>global clock</a>.
+      </p>
+      <p class="issue">
+        Is this at odds with those <a>time values</a> being relative to
+        <code>navigationStart</code> and with <code>requestAnimationFrame</code>
+        using the same time as <code>document.timeline.currentTime</code>?
       </p>
     </section>