Why does my report subscription reset itself?

I set up an daily email performance report that is sent to a group email address.  When I first set up the report, it worked perfectly for the first two days.  Then we all stopped receiving it on day three.  I went in and checked the subscription that I had set up, and for some unknown reason, the email address had been removed and the "Active" checkbox had become unchecked.

I reset the subscription to send daily to the same address again, and for two days it worked, and then the same thing happened.  Has anyone else had an issue like this with report subscriptions?