diff --git a/app/controllers/experiments_controller.rb b/app/controllers/experiments_controller.rb
index 37603a9f4..13eb02177 100644
--- a/app/controllers/experiments_controller.rb
+++ b/app/controllers/experiments_controller.rb
@@ -332,13 +332,19 @@ class ExperimentsController < ApplicationController
     dst_experiment = @experiment.project.experiments.find(params[:to_experiment_id])
     return render_403 unless can_manage_experiment?(dst_experiment)
 
-    @experiment.with_lock do
+    @experiment.transaction do
       params[:my_module_ids].each do |id|
         my_module = @experiment.my_modules.find(id)
         return render_403 unless can_move_my_module?(my_module)
 
         modules_to_move[id] = dst_experiment.id
       end
+      # Make sure that locks are acquired always in the same order
+      if dst_experiment.id < @experiment.id
+        dst_experiment.lock! && @experiment.lock!
+      else
+        @experiment.lock! && dst_experiment.lock!
+      end
       @experiment.move_modules(modules_to_move, current_user)
       @experiment.workflowimg.purge
 
diff --git a/app/controllers/protocols_controller.rb b/app/controllers/protocols_controller.rb
index 944f87143..97ce37c15 100644
--- a/app/controllers/protocols_controller.rb
+++ b/app/controllers/protocols_controller.rb
@@ -1,4 +1,3 @@
-
 class ProtocolsController < ApplicationController
   include RenamingUtil
   include ActionView::Helpers::TextHelper
@@ -165,7 +164,6 @@ class ProtocolsController < ApplicationController
   end
 
   def show
-
     respond_to do |format|
       format.json { render json: @protocol, serializer: ProtocolSerializer, user: current_user }
       format.html
@@ -253,9 +251,7 @@ class ProtocolsController < ApplicationController
   end
 
   def delete_steps
-    @protocol.my_module.lock!
-
-    Protocol.transaction do
+    @protocol.with_lock do
       team = @protocol.team
       previous_size = 0
       @protocol.steps.each do |step|
@@ -273,7 +269,6 @@ class ProtocolsController < ApplicationController
 
         # skip adjusting positions after destroy as this is a bulk delete
         step.skip_position_adjust = true
-
         step.destroy!
       end
 
diff --git a/app/models/my_module.rb b/app/models/my_module.rb
index 413463669..ed883bf4e 100644
--- a/app/models/my_module.rb
+++ b/app/models/my_module.rb
@@ -13,9 +13,6 @@ class MyModule < ApplicationRecord
   include Assignable
   include Cloneable
 
-  ID_PREFIX = 'TA'
-  include PrefixedIdModel
-
   attr_accessor :transition_error_rollback
 
   enum state: Extends::TASKS_STATES
diff --git a/app/services/repository_rows/my_module_assign_unassign_service.rb b/app/services/repository_rows/my_module_assign_unassign_service.rb
index 905fc81ad..2274bca1d 100644
--- a/app/services/repository_rows/my_module_assign_unassign_service.rb
+++ b/app/services/repository_rows/my_module_assign_unassign_service.rb
@@ -86,23 +86,19 @@ module RepositoryRows
 
       return [] unless params[:rows_to_assign]
 
-      my_module.with_lock do
-        unassigned_rows = @repository.repository_rows
-                                     .active
-                                     .joins("LEFT OUTER JOIN my_module_repository_rows "\
-                                            "ON repository_rows.id = my_module_repository_rows.repository_row_id "\
-                                            "AND my_module_repository_rows.my_module_id = #{my_module.id.to_i}")
-                                     .where(my_module_repository_rows: { id: nil })
-                                     .where(id: @params[:rows_to_assign])
+      unassigned_rows = @repository.repository_rows
+                                   .active
+                                   .joins("LEFT OUTER JOIN my_module_repository_rows " \
+                                          "ON repository_rows.id = my_module_repository_rows.repository_row_id " \
+                                          "AND my_module_repository_rows.my_module_id = #{my_module.id.to_i}")
+                                   .where(my_module_repository_rows: { id: nil })
+                                   .where(id: @params[:rows_to_assign])
 
-        return [] unless unassigned_rows.any?
+      return [] unless unassigned_rows.any?
 
-        unassigned_rows.find_each do |repository_row|
-          MyModuleRepositoryRow.create!(my_module: my_module,
-                                        repository_row: repository_row,
-                                        assigned_by: @user)
-          assigned_names << repository_row.name
-        end
+      unassigned_rows.find_each do |repository_row|
+        my_module.my_module_repository_rows.create!(repository_row: repository_row, assigned_by: @user)
+        assigned_names << repository_row.name
       end
 
       return [] if assigned_names.blank?