update: the problem appears to be that @paulo_caelum and @Lalala_Brrrie twitted at the exact same time, but @Lalala_Brrrie has used sms. then the original twitt by @paulo_caelum (this one: http://twitpic.com/388q1f) was replaced by @Lalala_Brrrie's twitt.
twitt: http://twitter.com/#!/Lalala_Brrrie/status/5617267836456961
@paulo_caleum timeline showing the bug: http://twitter.com/#!/paulo_caelum
that's all folks