Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1
I'm not observing this problem in coreutils 8.29, the current version. Please
give that a try. If you're still seeing the problem, please let us know your
platform, how you built coreutils, and your locale (run the 'locale' command).
Thanks.