diff --git a/lib/ancestry/instance_methods.rb b/lib/ancestry/instance_methods.rb
index 08427c2b..0965ccda 100644
--- a/lib/ancestry/instance_methods.rb
+++ b/lib/ancestry/instance_methods.rb
@@ -62,6 +62,7 @@ def touch_ancestors_callback
 
     # Counter Cache
     def increase_parent_counter_cache
+      return if ancestry_callbacks_disabled?
       self.ancestry_base_class.increment_counter _counter_cache_column, parent_id
     end
 
@@ -78,14 +79,18 @@ def decrease_parent_counter_cache
     end
 
     def update_parent_counter_cache
-      changed = saved_change_to_attribute?(self.ancestry_base_class.ancestry_column)
-
-      return unless changed
+      # @_trigger_update_callback comes from activerecord, which makes sure only once decrement when concurrent deletion.
+      # but @_trigger_update_callback began after rails@5.1.0.alpha.
+      # https://github.com/rails/rails/blob/v5.2.0/activerecord/lib/active_record/persistence.rb#L340
+      # https://github.com/rails/rails/pull/27248
+      return if defined?(@_trigger_update_callback) && !@_trigger_update_callback
+      return unless saved_change_to_attribute?(self.ancestry_base_class.ancestry_column)
 
       if parent_id_was = parent_id_before_last_save
         self.ancestry_base_class.decrement_counter _counter_cache_column, parent_id_was
       end
 
+      # TODO: use increase_parent_counter_cache instead?
       parent_id && self.ancestry_base_class.increment_counter(_counter_cache_column, parent_id)
     end