[eashwar]

My Lumia 525 screen sometimes zooms in automatically and cannot be resolved until reboot!

[Aryan Salooja]

Maybe you have left the screen magnifier setings on.... Switch it off in ease of access setings..

[maccentris]

The screen magnifier controls this. If you wait a few seconds after it happens, double-tapping your screen will hopefully bring it back to normal. This became a problem for me when I was using the "double-tap screen to wake phone" feature. It keep doing this while in my pocket, I was perplexed. Your question helped me pinpoint the issue and of course, realize that the other feature was interfering while the phone wasn't even intended to be used while in my pocket!