There's a $file variable set in /etc/profile.d/bash-completion which is not unset, and thus ends in the user's environment. I noticed it because it screwed a oneliner i did which was using a $file variable too (which was supposed to be unset at the begining). Trivial patch follows.
Created attachment 84198 [details, diff] bash-completion-unset-file.patch
bug-wranglers@gentoo.or
Fixed in app-shells/bash-completion-20060301-r3 which is now unmasked.