I've noticed that the "Check all comments now" button under the admin/Comments module is badly broken.
Using debug mode, and network sniffing, I:
* Submitted a new comment as a non-logged in user
* Saw Akismet being checked, a "false" being returned, and the commet let through/marked as published (all good so far)
I then went into the admin comment module, and hit the "Check all comments now" button, and saw:
* Gallery check with Akismet, again
* Akismet returns "false", but Gallery marks the comment as spam anyway
Being that both calls are to the same function, $akismet->checkComment(), I don't get how this is broken, but am willing to help out to solve this bug, because I quite annoyingly lost ALL my comments the other night due to hitting this button, and then "Delete all spam" under moderation.