As I can see from bug #355141, would be interesting to know coreutils version in emerge --info as it provides important things like "install". Thanks Reproducible: Always
Those packages are defined here: http://sources.gentoo.org/cgi-bin/viewvc.cgi/gentoo-x86/profiles/info_pkgs?view=log Not really a sys-apps/portage bug.
I guess the reason it's never been added is that the behavior is supposed to be constant regardless of version, and any deviation from that must be a rare and short-lived regression.
in general that's a fine position, but in this specific the behavior can crop up from time to time. however, i'm not sure including the coreutils output would have made any difference at all to the bug development. a simple search of bugzilla for "install: will not overwrite just-created" would however have thrown many matches that'd of narrowed down the issue.
Well, in that case, looking at bug 319443 that points to coreutils-8.4 and automake-1.11 introducing this behavior, looks surprising to me that I was unable to reproduce bug #355141 with their respective 8.7 and 1.11.1 :-/