diff --git a/lib/model.js b/lib/model.js
index 8a3592de09d..d54f5206146 100644
--- a/lib/model.js
+++ b/lib/model.js
@@ -2126,7 +2126,7 @@ Model.bulkWrite = function(ops, options, callback) {
         try {
           op['updateMany']['filter'] = cast(_this.schema,
             op['updateMany']['filter']);
-          op['updateMany']['update'] = castUpdate(_this.schema, op['updateMany']['filter'], {
+          op['updateMany']['update'] = castUpdate(_this.schema, op['updateMany']['update'], {
             strict: _this.schema.options.strict,
             overwrite: false
           });