diff --git a/app/controllers/study_groups_controller.rb b/app/controllers/study_groups_controller.rb
index 904b7f2c..26cb7615 100644
--- a/app/controllers/study_groups_controller.rb
+++ b/app/controllers/study_groups_controller.rb
@@ -22,9 +22,8 @@ class StudyGroupsController < ApplicationController
 
   def update
     myparams = study_group_params
-    myparams[:external_users] =
-      @study_group.study_group_memberships.where(id: myparams[:study_group_membership_ids].compact_blank).includes(:user).map(&:user)
-    myparams.delete(:study_group_membership_ids)
+    @members = @study_group.study_group_memberships.includes(:user)
+    myparams[:external_users] = @members.where(id: myparams[:study_group_membership_ids].compact_blank).map(&:user)
     update_and_respond(object: @study_group, params: myparams)
   end