New version of Akismet plugin released – 2.5.6:

summary from the change log:

  • Prevent retry scheduling problems on sites where wp_cron is misbehaving
  • Preload mshot previews
  • Modernize the widget code
  • Fix a bug where comments were not held for moderation during an error condition
  • Improve the UX and display when comments are temporarily held due to an error
  • Make the Check For Spam button force a retry when comments are held due to an error
  • Handle errors caused by an invalid key
  • Don’t retry comments that are too old
  • Improve error messages when verifying an API key

I’ll file a ticket to request updating to the 2.5.6 tag.