I suspect that <http://askubuntu.com/q/759795> is related. In that case LANG is set to "en_IN", which is a perfectly valid name of the English/India UTF-8 locale.
$ cat /usr/share/i18n/SUPPORTED | grep en_IN en_IN UTF-8
Changing LANG to "en_IN.UTF-8" makes the error messages go away.
So there seems to be an incorrect locale validity test somewhere in the code.
I suspect that <http:// askubuntu. com/q/759795> is related. In that case LANG is set to "en_IN", which is a perfectly valid name of the English/India UTF-8 locale.
$ cat /usr/share/ i18n/SUPPORTED | grep en_IN
en_IN UTF-8
Changing LANG to "en_IN.UTF-8" makes the error messages go away.
So there seems to be an incorrect locale validity test somewhere in the code.