toplevel constant Parent referenced by Parent::Parent

I'm upgrading from 1.1.6 to 1.2.6 and I'm getting a strange warning.

<code>
activerecord/lib/active_record/base.rb:1361: warning: toplevel constant
Parent referenced by Parent::Parent
</code>

Where Parent is the top-level class in an STI hierarchy.

I also have:
class Child1 < Parent
class Child2 < Child1

In Parent I have several class convenience methods:

<code>
  class <<self

    def new_parent(class_name, args={})
      send("new_#{class_name}", args)
    end

    def new_child1(args={})
      Child1.new(args.merge(:child1_specific_configurations => args))
    end

    def new_child2(args={})
      Child2.new(args.merge(:child2_specific_configurations => args))
    end
end
</code>

Should I be worried about the warning? I'm not sure that I understand it
and I don't see it with my other STI classes. The above methods aren't
expressly required, they just make working the class hierarchy easier.

Thanks in advance.

Erik