pkg_install issues during pkg_rr

[Richard PALO <richard%netbsd.org@localhost>]

a recent pkg_rr bombed out here:
> RR> Selecting pkg_install (pkgtools/pkg_install
> pkgtools/pkg_install) as next package to replace
> Usage: dirname [ path ]
> *** No package directory 'pkgtools/pkg_install
> pkgtools/pkg_install' for pkg_install.
> *** Please read the errors listed above, fix the problem,
> *** then re-run pkg_rolling-replace to continue.

so I manually built it but it doesn't seem to want to replace:
> richard@omnis:/home/richard/src/pkgsrc/pkgtools/pkg_install$ bmake replace
> ===> Replacing for pkg_install-20160410nb1
> => Becoming ``root'' to make su-replace (pfexec)
> Creating binary package: pkg_install-20150901nb1
> Creating package /tmp/pkgsrc/pkgtools/pkg_install/work/pkg_install-20150901nb1
> ===> Updating using binary package of pkg_install-20160410nb1
> /tmp/pkgsrc/pkgtools/pkg_install/work/pkg_install-20160410/add/pkg_add -K /opt/local/pkg -U -D /tmp/pkgsrc/pkgtools/pkg_install/work/.packages/pkg_install-20160410nb1.tgz
> pkg_add: Conflicting PLIST with pkg_install-20150901: man/man1/pkg_add.1
> pkg_add: 1 package addition failed
> *** Error code 1

unless I'm dreaming, I thought this has worked (for a while, anyway)...
I remember it *used* to be a pain...

Any ideas (on avoiding a new bootstrap)
-- 
Richard PALO