I had this happen today too. I think its happened before but I don't have all of the details. In the past I know it has removed jim@hotmail.com when it should have removed jimbeam@hotmail.com and vice versa, but todays action was completely different. The names were as far from being alike as two names could be.
I suspect it has something to do with the timing surrounding the writing to the tmp.from file.
I had a strange occurrence this morning with one of my mailing lists. User2 unsubscribed, and the list removed User1, who is another list member from the same domain. The log file entry is below (names/domains changed to protect the innocent):
X997 user1@domain.com 24689 user2@domain.com Removed: user1@domain.com
You have been removed from the list..X unsubscribe: 997 user1@domain.com 24689 user2@domain.com by: user2@domain.com Fri Feb 15 09:31:56 EST 2002
Why would this happen?