diff --git a/lib/media/media_source_engine.js b/lib/media/media_source_engine.js
index 8aed3d1ca0..f65664479b 100644
--- a/lib/media/media_source_engine.js
+++ b/lib/media/media_source_engine.js
@@ -845,7 +845,7 @@ shaka.media.MediaSourceEngine = class {
       this.append_(contentType, data);
     });
 
-    if (goog.DEBUG && reference) {
+    if (goog.DEBUG && reference && !reference.isPreload()) {
       const bufferedAfter = this.getBuffered_(contentType);
       const newBuffered = shaka.media.TimeRangesUtils.computeAddedRange(
           bufferedBefore, bufferedAfter);