i am affected by the same problem. i searched google and i found that many distros are affected (gentoo, debian and arch at least) but they solved it adding the locale settings in xorg.conf or evdev but my xorg contains the locale already. this happened after upgrade to 12.04 but i am not sure it is because precise evdev or even ubuntu. it's like a bug in xorg itself.
i am affected by the same problem. i searched google and i found that many distros are affected (gentoo, debian and arch at least) but they solved it adding the locale settings in xorg.conf or evdev but my xorg contains the locale already. this happened after upgrade to 12.04 but i am not sure it is because precise evdev or even ubuntu. it's like a bug in xorg itself.