When the Contacts email address changes, this updates the "Print Email Receipt" on the Contact with the updated Email address.

If the contact is linked to an Account Subscription or (contact) Subscription, then the related Subscription's "Print Receipt Email" address is also updated.

There are a few things that may stop this from happening.

1. The Print Email Receipt will only update from the Contact if the end date is greater than 180 days in the past and into the future.
2. The user doing the update of the email address did not have the permissions to update the related Account/Contact Subscription.
   To fix this:
   1. Make sure all users have one of the Payments2Us Permission Sets assigned to them, for example the Payments2Us Standard User.
   2. Make sure users profile have Read/Update access to the Account/Contact Subscription Objects.
3. When Payments2Us attempted to update the related Account/Contact Subscription, a custom Flow/Process Builder/Workflow on the Account/Contact Subscription tried to update the parent Account/Contact.  This in turned caused a recursion update error and the error will be logged in the "Error Log - Payments2Us".  
   To fix this, please see FAQ:  For program/area contactUpdate.printEmailReceiptUpdate