"I've reviewed our ongoing/solved investigations and can confirm there's currently no records of subscribers reporting that their Express Pick template is reverting back after changes have been made to it."

Wow.  What am I missing when the thread above this comment shows many people having the issue.  I believe the fix is to find the original template used by the worksheet and then replace it with the custom template created by the user, but keep the original name.  This is a daunting task as it needs to be done deep into the system.