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
 
diff --git a/test/unit/time_entry_activity_test.rb b/test/unit/time_entry_activity_test.rb
index 67e9258504..321dc12e0e 100644
--- a/test/unit/time_entry_activity_test.rb
+++ b/test/unit/time_entry_activity_test.rb
@@ -144,7 +144,7 @@ class TimeEntryActivityTest < ActiveSupport::TestCase
         parent_activity.id.to_s => {
           'parent_id' => parent_activity.id.to_s,
           'active' => '0',
-          'custom_field_values' => {'7' => ''}
+          'custom_field_values' => {'7' => '1'}
         }
       }
     )
@@ -158,7 +158,7 @@ class TimeEntryActivityTest < ActiveSupport::TestCase
         other_parent_activity.id.to_s => {
           'parent_id' => other_parent_activity.id.to_s,
           'active' => '0',
-          'custom_field_values' => {'7' => ''}
+          'custom_field_values' => {'7' => '1'}
         }
       }
     )
@@ -179,7 +179,7 @@ class TimeEntryActivityTest < ActiveSupport::TestCase
         parent_activity.id.to_s => {
           'parent_id' => parent_activity.id.to_s,
           'active' => '0',
-          'custom_field_values' => {'7' => ''}
+          'custom_field_values' => {'7' => '1'}
         }
       }
     )
@@ -196,4 +196,27 @@ class TimeEntryActivityTest < ActiveSupport::TestCase
     assert_equal 'Design2', project_activity.reload.name
     assert_equal 'Design3', parent_activity.reload.name
   end
+
+  def test_project_activity_should_not_create_with_same_value_as_system_activity
+    system_activity = TimeEntryActivity.find(9) # Design
+    assert_equal true, system_activity.active
+
+    custom_field_value = system_activity.custom_field_values.detect{|cfv| cfv.custom_field.id == 7}
+    assert_nil custom_field_value.value
+
+    project = Project.find(1)
+    assert_equal 0, project.time_entry_activities.count
+
+    assert_no_difference 'TimeEntryActivity.count' do
+      project.update_or_create_time_entry_activities(
+        {
+          '9' => {
+            'parent_id' => '9',
+            'active' => '1',
+            'custom_field_values' => {'7' => ''}
+          }
+        }
+      )
+    end
+  end
 end