diff --git a/app/controllers/sample_types_controller.rb b/app/controllers/sample_types_controller.rb
index e5645ff3b4..7cb6b3ec82 100644
--- a/app/controllers/sample_types_controller.rb
+++ b/app/controllers/sample_types_controller.rb
@@ -227,6 +227,7 @@ def update_sample_json_metadata
 
   def check_if_locked
     @sample_type ||= SampleType.find(params[:id])
+    @sample_type.reload
     return unless @sample_type&.locked?
 
     error_message = 'This sample type is locked and cannot be edited right now.'
diff --git a/test/functional/sample_types_controller_test.rb b/test/functional/sample_types_controller_test.rb
index 56482357e5..d45b6cae6e 100644
--- a/test/functional/sample_types_controller_test.rb
+++ b/test/functional/sample_types_controller_test.rb
@@ -41,7 +41,7 @@ class SampleTypesControllerTest < ActionController::TestCase
       assert_enqueued_with(job: SampleTypeUpdateJob) do
         assert_difference('ActivityLog.count') do
           assert_difference('SampleType.count') do
-            assert_difference('Task.count') do
+            assert_difference('Task.where(key: "template_generation").count') do
               post :create, params: { sample_type: { title: 'Hello!',
                                                      project_ids: @project_ids,
                                                      description: 'The description!!',
@@ -787,8 +787,8 @@ class SampleTypesControllerTest < ActionController::TestCase
       assert_response :success
     end
 
-    # Locking the sample type
-    @sample_type.set_lock
+    # lock the sample type by adding a fake update task
+    UpdateSampleMetadataJob.perform_later(@sample_type, @person.user, [])
     assert @sample_type.locked?
 
     %i[edit manage].each do |action|
diff --git a/test/functional/samples_controller_test.rb b/test/functional/samples_controller_test.rb
index a19271f42f..94a06d3323 100644
--- a/test/functional/samples_controller_test.rb
+++ b/test/functional/samples_controller_test.rb
@@ -1591,10 +1591,9 @@ def rdf_test_object
 
     sample_type = FactoryBot.create(:simple_sample_type, contributor: person, project_ids: [project.id])
 
-    get :new, params: { sample_type_id: sample_type.id }
-    assert_response :success
+    # lock the sample type by adding a fake update task
+    UpdateSampleMetadataJob.perform_later(sample_type, person.user, [])
 
-    sample_type.set_lock
     get :new, params: { sample_type_id: sample_type.id }
     assert_redirected_to sample_types_path(sample_type)
     assert_equal flash[:error], 'This sample type is locked. You cannot edit the sample.'
diff --git a/test/unit/sample_test.rb b/test/unit/sample_test.rb
index 37799b1ed6..3daf68c5d5 100644
--- a/test/unit/sample_test.rb
+++ b/test/unit/sample_test.rb
@@ -1456,8 +1456,11 @@ class SampleTest < ActiveSupport::TestCase
   end
 
   test 'add sample to a locked sample type' do
-    sample_type = FactoryBot.create(:simple_sample_type, project_ids: [FactoryBot.create(:project).id], contributor: FactoryBot.create(:person))
-    sample_type.set_lock
+    person = FactoryBot.create(:person)
+    sample_type = FactoryBot.create(:simple_sample_type, project_ids: [FactoryBot.create(:project).id], contributor: person)
+
+    # lock the sample type by adding a fake update task
+    UpdateSampleMetadataJob.perform_later(sample_type, person.user, [])
     assert sample_type.locked?
 
     assert_no_difference('Sample.count') do
diff --git a/test/unit/sample_type_test.rb b/test/unit/sample_type_test.rb
index c506a74453..f5b7f93817 100644
--- a/test/unit/sample_type_test.rb
+++ b/test/unit/sample_type_test.rb
@@ -6,11 +6,6 @@ def setup
     @person = FactoryBot.create(:person)
     @project = @person.projects.first
     @project_ids = [@project.id]
-    Rails.cache.clear
-  end
-
-  def teardown
-    Rails.cache.clear
   end
 
   test 'validation' do
@@ -695,7 +690,7 @@ def teardown
     assert sample_type.new_record?
     refute sample_type.template_generation_task.pending?
 
-    assert_difference('Task.count', 1) do
+    assert_difference('Task.where(key: "template_generation").count', 1) do
       assert_enqueued_with(job: SampleTemplateGeneratorJob, args: [sample_type]) do
         disable_authorization_checks { sample_type.save! }
         assert sample_type.reload.template_generation_task.pending?
@@ -1063,25 +1058,15 @@ def teardown
   test 'sample type is locked?' do
     sample_type = FactoryBot.create(:simple_sample_type, project_ids: @project_ids, contributor: @person)
     refute sample_type.locked?
-    sample_type.set_lock
+
+    # lock the sample type by adding a fake update task
+    UpdateSampleMetadataJob.perform_later(sample_type, @person.user, [])
+
     assert sample_type.locked?
     refute sample_type.valid?
     assert sample_type.errors.added?(:base, 'This sample type is locked and cannot be edited right now.')
   end
 
-  test 'update locked sample type' do
-    sample_type = FactoryBot.create(:simple_sample_type, project_ids: @project_ids, contributor: @person)
-    (1..10).each do |i|
-      FactoryBot.create(:sample, sample_type: sample_type, project_ids: @project_ids, title: "Sample #{i}")
-    end
-    sample_type.with_lock do
-      # sample_type.samples << FactoryBot.create(:sample, sample_type: sample_type, project_ids: @project_ids, title: 'Sample 11')
-      # sample_type.title = 'Updated title'
-      sample_type.sample_attributes.first.title = 'Updated title'
-      sample_type.save!
-    end
-  end
-
   private
 
   # sample type with 3 samples