noticed that the latest version of iOS on my iPhone introduced an unexpected bug. Previously, if you are in mail and you tapped on a link in your email, your phone would bring up Safari or Facebook or whatever app the link was calling, and at the top left corner of the app, there would be a button to go back to your mail app or the app previous app.

Instead, my phone now has "search" at the top left corner and if I tap on it, it brings up a blank page and the only way to get out of that blank page is to press the home button.

I’m not having that problem with mine. I still have the arrow that takes me back to the mail app. I just tried it on a couple emails. One took me to an app and one to safari. Both had the arrow to take me back to the mail app.

keep a lookout for that