diff --git a/services/web/app/coffee/Features/Subscription/SubscriptionUpdater.coffee b/services/web/app/coffee/Features/Subscription/SubscriptionUpdater.coffee
index 299320f061..0e5530856c 100644
--- a/services/web/app/coffee/Features/Subscription/SubscriptionUpdater.coffee
+++ b/services/web/app/coffee/Features/Subscription/SubscriptionUpdater.coffee
@@ -33,7 +33,7 @@ module.exports = SubscriptionUpdater =
 		searchOps =
 			_id: subscriptionId
 		insertOperation =
-			{ $push: { member_ids: { $each: memberIds } } }
+			{ $addToSet: { member_ids: { $each: memberIds } } }
 
 		Subscription.findAndModify searchOps, insertOperation, (err, subscription) ->
 			return callback(err) if err?
diff --git a/services/web/test/unit/coffee/Subscription/SubscriptionUpdaterTests.coffee b/services/web/test/unit/coffee/Subscription/SubscriptionUpdaterTests.coffee
index 1a67a183b4..7b3acf1b78 100644
--- a/services/web/test/unit/coffee/Subscription/SubscriptionUpdaterTests.coffee
+++ b/services/web/test/unit/coffee/Subscription/SubscriptionUpdaterTests.coffee
@@ -180,7 +180,7 @@ describe "SubscriptionUpdater", ->
 				searchOps =
 					_id: @subscription._id
 				insertOperation =
-					{ $push: { member_ids: { $each: [@otherUserId] } } }
+					{ $addToSet: { member_ids: { $each: [@otherUserId] } } }
 				@findAndModifyStub.calledWith(searchOps, insertOperation).should.equal true
 				done()