diff --git a/app/services/activities_service.rb b/app/services/activities_service.rb
index 103d42ddd..80ebd1f05 100644
--- a/app/services/activities_service.rb
+++ b/app/services/activities_service.rb
@@ -18,8 +18,8 @@ class ActivitiesService
         query = query.where('project_id IN (?)', subjects_with_children['Project'])
         subjects_with_children.except!('Project')
       end
-      where_condition = subjects_with_children.map { '(subject_type = ? AND subject_id IN(?))' }.join(' OR ')
-      where_arguments = subjects_with_children.flatten
+      where_condition = subjects_with_children.to_h.map { '(subject_type = ? AND subject_id IN(?))' }.join(' OR ')
+      where_arguments = subjects_with_children.to_h.flatten
       if subjects_with_children[:my_module]
         where_condition = where_condition.concat(' OR (my_module_id IN(?))')
         where_arguments << subjects_with_children[:my_module]
@@ -71,8 +71,8 @@ class ActivitiesService
     subjects_with_children = load_subjects_children('MyModule': [my_module.id])
     query = Activity.where(project: my_module.experiment.project)
     query.where(
-      subjects_with_children.map { '(subject_type = ? AND subject_id IN(?))' }.join(' OR '),
-      *subjects_with_children.flatten
+      subjects_with_children.to_h.map { '(subject_type = ? AND subject_id IN(?))' }.join(' OR '),
+      *subjects_with_children.to_h.flatten
     )
   end
 end