You need look no further than paid search. In paid search, google wraps your site's link in their own redirect mechanisms, optimizer and such. If I tap a paid search link in Safari, it leads directly to our app. However, should I copy and paste that very same link into another app and try to open it from there, it will lead me to our mobile website instead.
Imagine that X is your universal link.
R() is a redirect function.
R(X), then, is your unviersal link wrapped in some redirect scheme.
If you tap X in any app, it leads to your app.
If you tap R(X) in Safari, it leads to your app.
If you tap R(X) in any third party app, it leads to web-mobile.
I would love to have R(X) lead always to our app, no matter the application in which it is executed. Otherwise how are we supposed to bypass any social media/emailing system's own redirects?