diff --git a/packages/mongo-livedata/oplog_observe_driver.js b/packages/mongo-livedata/oplog_observe_driver.js
index 7512fe74f4..5c83afdd6e 100644
--- a/packages/mongo-livedata/oplog_observe_driver.js
+++ b/packages/mongo-livedata/oplog_observe_driver.js
@@ -333,8 +333,6 @@ _.extend(OplogObserveDriver.prototype, {
   },
   _handleDoc: function (id, newDoc) {
     var self = this;
-    newDoc = _.clone(newDoc);
-
     var matchesNow = newDoc && self._matcher.documentMatches(newDoc).result;
 
     var publishedBefore = self._published.has(id);