When I receive notifications, plug in power, or manually turn on my phone display, the lock screen stays on forever (until battery runs out). My display timeout setting is set to 15 seconds (the lowest). The normal display times out correctly, just not the lockscreen.
A month ago I enabled developer mode, but only used it to enable usb debugging and made an adb backup of my phone. The lockscreen still timed out after that and I have made no other modification to the settings since then. The phone has not ever been rooted. Developer mode is currently off. Virus protection is on, and I've only downloaded authorized apps from the store.
I tried turning on/off gestures, smart stay, removing phone from case, cleaning screen, etc. I have no idea what is causing the lock screen to stay on and not timeout.
Samsung Galaxy S5 SM-G900T android 5.0