I tried exporting again with the r115 release, but I am still experiencing the same reset behavior. I updated the .capx link above with the file I opened in the new r115 release.
How are you maintaining state in your app after the user clicks the back or windows button on the phone, and then comes back to your app?
BTW, this is from the app failure report I received...
A Windows Phone app is deactivated when the user presses the Start button or if the device timeout causes the lock screen to engage. A Windows Phone app is also deactivated with it invokes a Launcher or Chooser API.
A Windows Phone OS 7.0 app is tombstoned (terminated) when it is deactivated. A Windows Phone OS 7.1 or higher app becomes Dormant when it is deactivated but can be terminated by the system when resource use policy causes it to tombstone.
When activated after termination, the app must meet the requirements in Section 5.2.1 - Launch time.
For more information and best practices, see App activation and deactivation for Windows Phone.