Did you check how this bug was resolved? accountsservice (a-s) stores the last entered session type in both a-s and ~/.dmrc. As regards language, a-s stores languages and locales settings in both a-s and ~/.pam_environment. If you mount e.g. a USB with HOME, and ~/.dmrc and a-s respective ~/.pam_environment and a-s are out of sync, I think the current session and language are grabbed from a-s, so your students should know, after all.
So, to conclude, I'm not sure what it is you would write in that bug report.
@John
I think you did miss a few things.
Did you check how this bug was resolved? accountsservice (a-s) stores the last entered session type in both a-s and ~/.dmrc. As regards language, a-s stores languages and locales settings in both a-s and ~/.pam_environment. If you mount e.g. a USB with HOME, and ~/.dmrc and a-s respective ~/.pam_environment and a-s are out of sync, I think the current session and language are grabbed from a-s, so your students should know, after all.
So, to conclude, I'm not sure what it is you would write in that bug report.