diff --git a/app/controllers/access_permissions/projects_controller.rb b/app/controllers/access_permissions/projects_controller.rb
index c5f679ac7..56fa6c110 100644
--- a/app/controllers/access_permissions/projects_controller.rb
+++ b/app/controllers/access_permissions/projects_controller.rb
@@ -38,10 +38,10 @@ module AccessPermissions
         team: current_team
       )
 
-      # prevent role change if it would result in no users having the user management permission
+      # prevent role change if it would result in no manually assigned users having the user management permission
       new_user_role = UserRole.find(permitted_update_params[:user_role_id])
       if !new_user_role.has_permission?(ProjectPermissions::USERS_MANAGE) &&
-         @user_assignment.last_with_permission?(ProjectPermissions::USERS_MANAGE)
+         @user_assignment.last_with_permission?(ProjectPermissions::USERS_MANAGE, assigned: :manually)
         raise ActiveRecord::RecordInvalid
       end
 
@@ -106,8 +106,10 @@ module AccessPermissions
       user = @project.assigned_users.find(params[:user_id])
       user_assignment = @project.user_assignments.find_by(user: user, team: current_team)
 
-      # prevent deletion of last user that can manage users
-      raise ActiveRecord::RecordInvalid if user_assignment.last_with_permission?(ProjectPermissions::USERS_MANAGE)
+      # prevent deletion of last manually assigned user that can manage users
+      if user_assignment.last_with_permission?(ProjectPermissions::USERS_MANAGE, assigned: :manually)
+        raise ActiveRecord::RecordInvalid
+      end
 
       if @project.visible?
         user_assignment.update!(
diff --git a/app/controllers/access_permissions/protocols_controller.rb b/app/controllers/access_permissions/protocols_controller.rb
index 7966efe14..1c5e744ea 100644
--- a/app/controllers/access_permissions/protocols_controller.rb
+++ b/app/controllers/access_permissions/protocols_controller.rb
@@ -36,10 +36,10 @@ module AccessPermissions
         team: current_team
       )
 
-      # prevent role change if it would result in no users having the user management permission
+      # prevent role change if it would result in no manually assigned users having the user management permission
       new_user_role = UserRole.find(permitted_update_params[:user_role_id])
       if !new_user_role.has_permission?(ProtocolPermissions::USERS_MANAGE) &&
-         @user_assignment.last_with_permission?(ProtocolPermissions::USERS_MANAGE)
+         @user_assignment.last_with_permission?(ProtocolPermissions::USERS_MANAGE, assigned: :manually)
         raise ActiveRecord::RecordInvalid
       end
 
@@ -102,8 +102,10 @@ module AccessPermissions
       user = @protocol.assigned_users.find(params[:user_id])
       user_assignment = @protocol.user_assignments.find_by(user: user, team: current_team)
 
-      # prevent deletion of last user that can manage users
-      raise ActiveRecord::RecordInvalid if user_assignment.last_with_permission?(ProtocolPermissions::USERS_MANAGE)
+      # prevent deletion of last manually assigned user that can manage users
+      if user_assignment.last_with_permission?(ProtocolPermissions::USERS_MANAGE, assigned: :manually)
+        raise ActiveRecord::RecordInvalid
+      end
 
       Protocol.transaction do
         if @protocol.visible?
diff --git a/app/models/user_assignment.rb b/app/models/user_assignment.rb
index ccd6a35cf..a8c6f9f8b 100644
--- a/app/models/user_assignment.rb
+++ b/app/models/user_assignment.rb
@@ -20,17 +20,23 @@ class UserAssignment < ApplicationRecord
 
   validates :user, uniqueness: { scope: %i(assignable team_id) }
 
+  scope :with_permission, ->(permission) { joins(:user_role).where('? = ANY(user_roles.permissions)', permission) }
+
   def last_assignable_owner?
     assignable_owners.count == 1 && user_role.owner?
   end
 
-  def last_with_permission?(permission)
+  def last_with_permission?(permission, assigned: nil)
     return false if user_role.permissions.exclude?(permission)
 
-    assignable.user_assignments.joins(:user_role)
-              .where.not(user: user)
-              .where('? = ANY(user_roles.permissions)', permission)
-              .none?
+    user_assignments =
+      assignable.user_assignments.joins(:user_role)
+                .where.not(user: user)
+                .with_permission(permission)
+
+    user_assignments = user_assignments.where(assigned: assigned) if assigned
+
+    user_assignments.none?
   end
 
   private
diff --git a/app/views/access_permissions/partials/_member_field.html.erb b/app/views/access_permissions/partials/_member_field.html.erb
index 6c7f261f8..ee75ea869 100644
--- a/app/views/access_permissions/partials/_member_field.html.erb
+++ b/app/views/access_permissions/partials/_member_field.html.erb
@@ -34,7 +34,7 @@
                 </a>
               </li>
             <% end %>
-            <% if defined?(delete_path) && !assignment.last_assignable_owner?  %>
+            <% if defined?(delete_path) && !assignment.last_with_permission?(ProjectPermissions::USERS_MANAGE, assigned: :manually) %>
               <li role="separator" class="divider" data-hook="support-dropdown-separator"></li>
               <li>
                 <%= link_to delete_path, remote: true, method: :delete, data: { action: 'remote-destroy', target: "##{item_id}" } do %>