When I edit my .login_conf on fresh install to change locale it only change LANG parameter. My .login_conf: me:\ :charset=UTF-8:\ :lang=fr_FR.UTF-8: locale command output: LANG=fr_FR.UTF-8 LC_CTYPE="C" LC_COLLATE="C" LC_TIME="C" LC_NUMERIC="C" LC_MONETARY="C" LC_MESSAGES="C" LC_ALL=
As the reported arch is powerpc, it's likely that it was cross-compiled, and that was indeed broken, see bug #231965.
Could you please try installing 12.0-BETA3 and see if it fixes the problem? (Note that I'm relying on H/W being correctly set to "powerpc" when this was filed.)
Should be fixed in bug #231965, base r339489. Please reopen if it's not. *** This bug has been marked as a duplicate of bug 231965 ***