--- a/dom/animation/Animation.cpp
+++ b/dom/animation/Animation.cpp
@@ -194,17 +194,17 @@ Animation::SetStartTime(const Nullable<T
 
   CancelPendingTasks();
   if (mReady) {
     // We may have already resolved mReady, but in that case calling
     // MaybeResolve is a no-op, so that's okay.
     mReady->MaybeResolve(this);
   }
 
-  UpdateTiming(SeekFlag::NoSeek, SyncNotifyFlag::Async);
+  UpdateTiming(SeekFlag::DidSeek, SyncNotifyFlag::Async);
   if (IsRelevant()) {
     nsNodeUtils::AnimationChanged(this);
   }
   PostUpdate();
 }
 
 // https://w3c.github.io/web-animations/#current-time
 Nullable<TimeDuration>

--- a/testing/web-platform/meta/web-animations/timing-model/animations/set-the-animation-start-time.html.ini
+++ b/testing/web-platform/meta/web-animations/timing-model/animations/set-the-animation-start-time.html.ini
@@ -2,12 +2,8 @@
   type: testharness
   [Setting the start time of an animation without an active timeline]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1096776
 
   [Setting an unresolved start time an animation without an active timeline does not clear the current time]
     expected: FAIL
     bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1096776
-
-  [Setting the start time updates the finished state]
-    expected: FAIL
-    bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1267893