permissions on /dev/tty

[Joe Pfeiffer <pfeiffer@cs.nmsu.edu>]

I have a laptop with a recent Debian install, which seems to have
incorrect permissions on /dev/tty

crw--w---- 1 root tty 5, 0 Feb 16 08:51 /dev/tty

/lib/udev/rules.d/50-udev-default.rules contains the usual

SUBSYSTEM=="tty", KERNEL=="tty", GROUP="tty", MODE="0666"

More strangely, udevadm info /dev/tty contains (among other things, of course)

E: DEVPATH=/devices/virtual/tty/tty
E: DEVNAME=/dev/tty
E: DEVMODE=0666

Does anyone have any idea what might be changing the permissions?  Or
have some ideas on how I might look for it?

Thanks,