Question/possible bug on ActiveRecord serialize and STI

I've been running into a problem where ActiveRecord 2.3.5 isn't
deserializing a serialized column in derived classes:
    http://pastie.org/856463
I've been able to replicate this test with Ruby 1.8.6p369, 1.8.7p72,
and 1.8.7p174 on different systems, any thoughts?

Dustin Lundquist