The key event should be stopped propagation when it's been processed as an accelerator.

ui/views/widget/desktop_aura/desktop_native_widget_aura.cc

Index: ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
diff --git a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
index f77bde8e5ba3f4caff6ff53838adba50834191ae..75b259276b5e10896d0e7133be316669d7ed1be4 100644
--- a/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
+++ b/ui/views/widget/desktop_aura/desktop_native_widget_aura.cc
@@ -220,7 +220,7 @@ class FocusManagerEventHandler : public ui::EventHandler {
     Widget* widget = desktop_native_widget_aura_->GetWidget();
     if (widget && widget->GetFocusManager()->GetFocusedView() &&
         !widget->GetFocusManager()->OnKeyEvent(*event)) {
-      event->SetHandled();
+      event->StopPropagation();
     }
   }
 
@@ -1035,8 +1035,9 @@ void DesktopNativeWidgetAura::OnKeyEvent(ui::KeyEvent* event) {
     return;
 
   if (GetWidget()->HasFocusManager() &&
-      !GetWidget()->GetFocusManager()->OnKeyEvent(*event))
-    event->SetHandled();
+      !GetWidget()->GetFocusManager()->OnKeyEvent(*event)) {
+    event->StopPropagation();
+  }
 }
 
 void DesktopNativeWidgetAura::OnMouseEvent(ui::MouseEvent* event) {