GDM 3.8 just migrated to unstable and I am also hit by this bug. A workaround for logging in is to use an alternate logging manager for now. LightDM did the job well and does not pull a lot of additional dependencies.
I can't really add anything more to this bug report at this point, although if you guys need my logs or debug command output, please ask. Ghislain -- To UNSUBSCRIBE, email to debian-bugs-rc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org