I see the same thing with en_GB. I note that setting the language from gdm adds en_GB.UTF-8 to my .dmrc, which stops the complaining.
This is presumably therefore something from previous installs that is setting the language without the encoding, which the login session then complains about.
FWIW, I see this in /etc/environment:
LANGUAGE="en_GB:en"
So it's either this or something similar that needs to be handled on upgrade. I'm pretty sure it's not a language-selector bug though, so I'm going to move this to gdm.
I see the same thing with en_GB. I note that setting the language from gdm adds en_GB.UTF-8 to my .dmrc, which stops the complaining.
This is presumably therefore something from previous installs that is setting the language without the encoding, which the login session then complains about.
FWIW, I see this in /etc/environment:
LANGUAGE="en_GB:en"
So it's either this or something similar that needs to be handled on upgrade. I'm pretty sure it's not a language-selector bug though, so I'm going to move this to gdm.