I just attempted to update to panels-7.x-3.x-dev (2014-Dec-23) today via drush up, which failed with the following message:

File panels-7.x-3.x-dev.tar.gz_date=1419361981 is corrupt (wrong md5 checksum).

I'm using a relatively fresh Composer-installed Drush 6.5.0 under PHP 5.3.29 via MAMP. Have been successfully updating modules the same way all day without issue, including panels-7.x-3.4, so this caught me by surprise. Same error when trying drush up panels-7.x-3.x-dev on a CentOS staging server running Drush 6.2.0.

I understand that errors like this have been cropping up sporadically for various other contrib modules, but not sure where to raise the alert.