diff --git a/gfx/layers/apz/src/AsyncPanZoomController.cpp b/gfx/layers/apz/src/AsyncPanZoomController.cpp
index f7512aa223b1..eca1b2ed4180 100644
--- a/gfx/layers/apz/src/AsyncPanZoomController.cpp
+++ b/gfx/layers/apz/src/AsyncPanZoomController.cpp
@@ -1287,14 +1287,6 @@ nsEventStatus AsyncPanZoomController::OnScaleBegin(const PinchGestureInput& aEve
 nsEventStatus AsyncPanZoomController::OnScale(const PinchGestureInput& aEvent) {
   APZC_LOG("%p got a scale in state %d\n", this, mState);
 
-  // Only the root APZC is zoomable, and the root APZC is not allowed to have
-  // different x and y scales. If it did, the calculations in this function
-  // would have to be adjusted (as e.g. it would no longer be valid to take
-  // the minimum or maximum of the ratios of the widths and heights of the
-  // page rect and the composition bounds).
-  MOZ_ASSERT(mFrameMetrics.IsRootScrollable());
-  MOZ_ASSERT(mFrameMetrics.GetZoom().AreScalesSame());
-
   if (HasReadyTouchBlock() && !CurrentTouchBlock()->TouchActionAllowsPinchZoom()) {
     return nsEventStatus_eIgnore;
   }
@@ -1303,6 +1295,14 @@ nsEventStatus AsyncPanZoomController::OnScale(const PinchGestureInput& aEvent) {
     return nsEventStatus_eConsumeNoDefault;
   }
 
+  // Only the root APZC is zoomable, and the root APZC is not allowed to have
+  // different x and y scales. If it did, the calculations in this function
+  // would have to be adjusted (as e.g. it would no longer be valid to take
+  // the minimum or maximum of the ratios of the widths and heights of the
+  // page rect and the composition bounds).
+  MOZ_ASSERT(mFrameMetrics.IsRootScrollable());
+  MOZ_ASSERT(mFrameMetrics.GetZoom().AreScalesSame());
+
   float prevSpan = aEvent.mPreviousSpan;
   if (fabsf(prevSpan) <= EPSILON || fabsf(aEvent.mCurrentSpan) <= EPSILON) {
     // We're still handling it; we've just decided to throw this event away.