iPhone 16 Pro Max glitches after iOS 18.4 update

Re: "16 pro max is getting stuck on few apps and back button funacnlity is not working properly.

Lock screen notification are shaking while scrolling them".

Wondering if updating your iPhone's iOS to the newest version may help:

About iOS 18 Updates - Apple Support says 18.4.1 (NB :it is always wise to Back up data, before updating)

First please update to the latest iOS 18.4.1, as brbo states as that does provide some bug fixes and performance enhancements.

Then perform a Forced Restart. The purpose of this is to resolve any software related issues that can be causing this. It essentially forces your iPhone to power off and back on, refreshing the system and files, along with deleting any corrupt ones.

• Press and quickly release the Volume Up Button
• Press and quickly release the Volume Down Button
• Press and hold the Side Button until you see the Apple Logo