Dell Latitude E6400 Fn-F8 (display toggle) generates duplicate events

If I press Fn-F8 (display toggle) once while running X, a duplicate keypress and keyrelease event is produced for it after hitting any other key.

So the following actual keypresses:
Press Fn-F8
Release Fn-F8
Press return
Release return

generate this keypress sequence:

Press Fn-F8
Release Fn-F8
Press Fn-F8
Release Fn-F8
Press return
Release return

The duplicate press and release event is only generated after I press another key.

If X is not running and I'm on the console, the duplicate keypress and -release event is generated immediately.

Attaching relevant output of xev and showkey.

ProblemType: Bug
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: STAC92xx Analog [STAC92xx Analog]
   Subdevices: 2/2
   Subdevice #0: subdevice #0
   Subdevice #1: subdevice #1
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: kai 1901 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf6adc000 irq 21'
   Mixer name : 'Intel G45 DEVCTG'
   Components : 'HDA:111d76b2,10280233,00100302 HDA:80862802,80860101,00100000'
   Controls : 24
   Simple ctrls : 15
Date: Tue Mar 9 21:52:39 2010
DistroRelease: Ubuntu 10.04
HibernationDevice: RESUME=UUID=84850757-fc9c-4161-b84e-bbd91d0ae069
InstallationMedia: Ubuntu 10.04 "Lucid Lynx" - Alpha amd64 (20091209)
MachineType: Dell Inc. Latitude E6400
Package: linux-image-2.6.32-16-generic 2.6.32-16.24
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-16-generic root=UUID=68c17dde-1bec-405b-9c58-e3a2e72a7d4d ro crashkernel=384M-2G:64M,2G-:128M quiet splash
ProcEnviron:
 LANGUAGE=de_DE:de:en_GB:en
 PATH=(custom, user)
 LANG=de_DE.utf8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-16.24-generic
Regression: No
RelatedPackageVersions: linux-firmware 1.32
Reproducible: Yes
SourcePackage: linux
TestedUpstream: Yes
Uname: Linux 2.6.32-16-generic x86_64
dmi.bios.date: 05/11/2009
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A14
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA14:bd05/11/2009:svnDellInc.:pnLatitudeE6400:pvr:rvnDellInc.:rn:rvr:cvnDellInc.:ct8:cvr:
dmi.product.name: Latitude E6400
dmi.sys.vendor: Dell Inc.