diff --git a/app/models/enumeration.rb b/app/models/enumeration.rb
index 5f0e023ed9..534d8239e1 100644
--- a/app/models/enumeration.rb
+++ b/app/models/enumeration.rb
@@ -117,7 +117,7 @@ class Enumeration < ActiveRecord::Base
   # Does the +new+ Hash have the same custom values as the previous Enumeration?
   def self.same_custom_values?(new, previous)
     previous.custom_field_values.each do |custom_value|
-      if custom_value.value != new["custom_field_values"][custom_value.custom_field_id.to_s]
+      if custom_value.to_s != new["custom_field_values"][custom_value.custom_field_id.to_s].to_s
         return false
       end
     end
diff --git a/test/functional/project_enumerations_controller_test.rb b/test/functional/project_enumerations_controller_test.rb
index 3c4f44f32e..b82dc50929 100644
--- a/test/functional/project_enumerations_controller_test.rb
+++ b/test/functional/project_enumerations_controller_test.rb
@@ -93,6 +93,26 @@ class ProjectEnumerationsControllerTest < Redmine::ControllerTest
     assert_nil project.time_entry_activities.find_by_name("QA"), "Custom QA activity created when it wasn't modified"
   end
 
+  def test_update_should_not_create_project_specific_activities_when_setting_empty_value_in_custom_field_with_default_value_of_nil
+    system_activity = TimeEntryActivity.find(9) # Design
+    custom_field_value = system_activity.custom_field_values.detect{|cfv| cfv.custom_field.id == 7}
+    assert_nil custom_field_value.value
+
+    assert_no_difference 'TimeEntryActivity.count' do
+      @request.session[:user_id] = 2 # manager
+      put(
+        :update,
+        :params => {
+          :project_id => 1,
+          :enumerations => {
+            "9" => {"parent_id" => "9", "custom_field_values" => {"7" => ""}, "active" => "1"}
+          }
+        }
+      )
+      assert_response :redirect
+    end
+  end
+
   def test_update_will_update_project_specific_activities
     @request.session[:user_id] = 2 # manager