Newer git is more picky about what constitutes a well-formed tag.
coreutils.git was created by older conversion tools that took shortcuts
in creating tags that now trigger warnings/failures with newer git (276
such broken tags).  See these threads in automake and findutils for
comparison, using a script from Kyle McKay to recreate back-dated fixed
tags of the same name:

https://lists.gnu.org/archive/html/findutils-patches/2016-10/msg00004.html
https://lists.gnu.org/archive/html/findutils-patches/2016-10/msg00014.html
https://lists.gnu.org/archive/html/bug-automake/2016-06/msg00004.html
https://lists.gnu.org/archive/html/bug-automake/2016-10/msg00003.html

I tried to correct the broken tags in coreutils.git, but unlike the
other two repositories, coreutils.git is more strongly locked down, and
complains with my attempt to update tags, with messages like:

remote: *** Deleting a tag is not allowed in this repository
remote: error: hook declined to update refs/tags/textutils-1_12_1

I'm hoping Jim knows the magic for how to (temporarily) suspend the
hooks and make the correction; in the meantime, I'm opening this bug
report to track that we still need to do the work.

Jim, feel free to take discussion offline, since configuration to
temporarily weaken hooks may not be the best idea to publically archive...

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org