diff --git a/lib/ancestry/instance_methods.rb b/lib/ancestry/instance_methods.rb
index f7244bc2..231276eb 100644
--- a/lib/ancestry/instance_methods.rb
+++ b/lib/ancestry/instance_methods.rb
@@ -296,7 +296,8 @@ def unscoped_descendants
 
     # Validates the ancestry, but can also be applied if validation is bypassed to determine if children should be affected
     def sane_ancestry?
-      ancestry.nil? || (ancestry.to_s =~ Ancestry::ANCESTRY_PATTERN && !ancestor_ids.include?(self.id))
+      ancestry_value = read_attribute(self.ancestry_base_class.ancestry_column)
+      ancestry_value.nil? || (ancestry_value.to_s =~ Ancestry::ANCESTRY_PATTERN && !ancestor_ids.include?(self.id))
     end
 
     def unscoped_find id
diff --git a/test/concerns/has_ancestry_test.rb b/test/concerns/has_ancestry_test.rb
index 7593e4a9..4e7c8a51 100644
--- a/test/concerns/has_ancestry_test.rb
+++ b/test/concerns/has_ancestry_test.rb
@@ -57,6 +57,18 @@ def test_descendants_move_with_node
     end
   end
 
+  def test_set_parent_with_non_default_ancestry_column
+    AncestryTestDatabase.with_model :depth => 3, :width => 3, :ancestry_column => :alternative_ancestry do |model, roots|
+      root1, root2, root3 = roots.map(&:first)
+      assert_no_difference 'root1.descendants.size' do
+        assert_difference 'root2.descendants.size', root1.subtree.size do
+          root1.parent = root2
+          root1.save!
+        end
+      end
+    end
+  end
+
   def test_setup_test_nodes
     AncestryTestDatabase.with_model :depth => 3, :width => 3 do |model, roots|
       assert_equal Array, roots.class