Another issue with the current tracking of urls in transactional emails for us is that it breaks magic links when there is a registered handler for the url (ie app installed). This means that users that have the app installed can never successfully login because when the app opens, the link is no longer valid as it was already accessed once (I suppose as part of the redirection). The work-around would be to allow magic links to be used more than once, which is not great from a security perspective.