Drush updates core successfully to 7.32 but is still 7.31 I'm developing a site on Drupal 7 and using drush 7.0-dev to keep the core and modules up to date. I've run drush pm-update several times successfully in the past, until Drupal core version 7.32 came out. Everything seems to go fine and drush reports no errors, but the version still stays at 7.31 after the update.

Here's the output of two consecutive runs:

me@mybox:/var/www/customer$ drush pm-update
 Name    Installed Version  Proposed version  Message
 Drupal  7.31               7.32              SECURITY UPDATE available


Update information last refreshed: Thu, 10/23/2014 - 20:21
Code updates will be made to drupal core.
WARNING:  Updating core will discard any modifications made to Drupal core files, most noteworthy among these are .htaccess and robots.txt.  If you have made any modifications 
to these files, please back them up before updating so that you can re-create your modifications in the updated version of the file.
Note: Updating core can potentially break your site. It is NOT recommended to update production sites without prior testing.

Do you really want to continue? (y/n): y
Project drupal was updated successfully. Installed version is now 7.32.
Backups were saved into the directory /home/me/drush-backups/customer/20141023172524/drupal.                                                                                           [ok]
No database updates required                                                                                                                                                           [success]
'all' cache was cleared.                                                                                                                                                               [success]
Finished performing updates.                                                                                                                                                           [ok]
me@mybox:/var/www/customer$ drush pm-update
 Name    Installed Version  Proposed version  Message
 Drupal  7.31               7.32              SECURITY UPDATE available


Update information last refreshed: Thu, 10/23/2014 - 20:25
Code updates will be made to drupal core.
WARNING:  Updating core will discard any modifications made to Drupal core files, most noteworthy among these are .htaccess and robots.txt.  If you have made any modifications 
to these files, please back them up before updating so that you can re-create your modifications in the updated version of the file.
Note: Updating core can potentially break your site. It is NOT recommended to update production sites without prior testing.

Do you really want to continue? (y/n):


Am I doing something wrong? Why is the core not updating? Where should I start troubleshooting? I haven't tried a manual update yet, because I'd really rather get drush working again. The server is running Debian 7 and PHP 5.4.
Try drush up drupal. That may do the trick.