asdf abfh vnc
It is a bug reported at #108928 and duplicated at #112955. Appears more like a GNOME issue than a VNC issue.
Solution #1: Use vnc4server -extension XFIXES
No, I did not try this because I simply do not want to change my client. The workaround basically requires you to remove tightvncserver and use vnc4server instead. Refer to this and this for more information.
Solution #2: Avoid executing gnome-session
Instead of running gnome-session, run the following commands in your xstartup script or manually in xterm:
Suggested by Randy at this link.
Solution #3: Reset the keyboard layout via gconf-editor
This solution works the best in my opinion, suggested by Will at this link. Open up gconf-editor in your X then navigate to:
desktop > gnome > peripherals > keyboard > kbd
You will probably be seeing empty value  or [us] for the layouts. Enter anything say foo, close the application and your problem should now be fixed.
- yc, one problem in life down