after_create bug (being called twice)

I'm seeing a very annoying and persistent bug where after_create
callbacks are called twice. I filed a lighthouse ticket, but didn't
get any responses from rails team members, so i'm hoping that posting
to the mailing list elicits more of a response. instead of rewriting
the entire explanation, i'll just reference my lighthouse ticket,
which includes code for a bare-bones app that demonstrates the
problem. (i've verified this bug exists in rails 2.3.2). if i am
missing something and this is somehow expected behavior, please let me
know...

https://rails.lighthouseapp.com/projects/8994/tickets/2765-after_create-callback-not-working-as-it-should

thanks..