I ran gem update --system to update to Rubygems 1.5.0 and after every time I run any bundle commands I get:
gem update --system
bundle
rvm/gems/ruby-1.8.7-p249/gems
This was posted on the issue tracker, by my count, 6 times now.
Here's the one that I've been linking everybody to: https://github.com/carlhuda/bundler/issues/issue/995