Lose access to Private directory after logging out then logging in again

1. Boot up to oneiric
2. Log in
3. Log out
4. Log in
5. Get a terminal, then...

~/Private$ ls
THIS DIRECTORY HAS BEEN UNMOUNTED TO PROTECT YOUR DATA -- Run mount.ecryptfs_private to mount again
~/Private$ cd ..
~$ mount.ecryptfs_private
keyctl_search: Required key not available
Perhaps try the interactive 'ecryptfs-mount-private'
~$ ecryptfs-mount-private
Enter your login passphrase:
Inserted auth tok with sig [7972913b8e43d166] into the user session keyring

Now I have access again. Not sure why I should be required to run two obscure command-line tools to regain access to something that I normally get on login.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: ecryptfs-utils 90-0ubuntu1
ProcVersionSignature: Ubuntu 3.0.0-9.15-generic 3.0.3
Uname: Linux 3.0.0-9-generic x86_64
Architecture: amd64
Date: Thu Sep 1 14:21:53 2011
EcryptfsInUse: Yes
ProcEnviron:
 PATH=(custom, user)
 LANG=en_AU.UTF-8
 SHELL=/bin/bash
SourcePackage: ecryptfs-utils
UpgradeStatus: Upgraded to oneiric on 2011-07-26 (37 days ago)