Posted by Matt Shultz on Macintouch
Working with a Genius at the Apple Store, we came up with a solid work-around for an issue (that I hope will become a recognized bug) in Address Book 6.1 under Lion 10.7.3.
Deleting members of a group does not effectively remove those members from receiving email. Apparently, AB 6.1 caches these names pretty firmly. As I initially was, this Store Genius was also surprised that a deletion in a previously created group was not honored. This is easily repeatable.
However, simply changing the name of the group after deleting the recipients desired, quitting AB 6.1 & then re-launching, will produce the desired results.
Here’s hoping this tip prevents disaster somewhere