Please Help - Same issue for years - Mail rule switches itself!

Question

This issue has plagued me with Apple Mail for years and I would like to finally resolve this to keep my sanity. Please help!
We have used the MobileMe family account (5 pack) for awhile and both my wife and I have our own unique email address that is set and we also have one combined account that we use as well. I have some rules in place to help keep the mail organized. Often we will get 1 e-mail for both of us (i.e. a message about a group we are both in or a sports team for our children) - it is sent to our joint account and then the Mail rule will handle putting them in both our boxes.
There is the one rule that keeps changing itself! It's maddening. Here is what I want to occur:
1. I get an e-mail to our joint MobileMe account.
2. The rule will move that specific message to my folder and then place a copy of that message in my wife's folder.
That's it. That's all that I want it to do.
Here is what I put in the mail rule description to make that happen:
IF "any" conditions met:
"Any recipient" is equal to "joint account e-mail address"
Perform following actions:
"Move message" to "my mailbox"
"copy message" to "her mailbox"
"Stop evaluating rules"
That's it. Here is where the problem ensues. This rule will actually work correctly for 1 or 2 times. Then what happens is somehow this rule actually changes itself and when I open up the rule description it will actually show:
"Move message" to "my mailbox"
"Copy message" to "my mailbox"
Ugh. So I end up getting two copies of the same thing and have to physically move it over. It seems so simple and I can't understand why it keeps switching itself.
I've had the issue ever since we had our family account and back to the Tiger operating system. I would love to get this fixed for good!

Answer 1

I may well have missed something, but it seems to me that the command to Copy to her mailbox should come before the command to Move to your mailbox. That way the source remains available until the final Move step. I cannot say why the Rule construction would change by itself, but I can see the possibility of confusion if the Move comes before the Copy.
Ernie