iPhone 6 auto-lock too early

My iPhone 6 has this nasty habit off switching off its screen too early. It’s been an issue in iOS 11 (probably even earlier) and unfortunately, it’s remains an issue in iOS 12.0.1.

I have auto-lock set to 5 minutes (the max setting in my list, apart from ‘never’). Regardless of that setting, after 2.5 minutes (yes, I timed it) the screen darkens and another 30 sec later it’s off entirely. I have never once been able to get this iPhone to respect my setting for auto-off. It happens regardless of battery power or charging.

Any ideas?

My iPad shows a different list. There the range goes up to 15 min. And the iPad seems to auto-lock at the right time. The iPhone 6 does not.

Do other iPhones show the same list? (30s, 1-5 min, never)

Do other iPhones respect that setting?

My iPhone X shows the same list (30s, 1-5 min, never). My iPad offers 2, 5, 10, 15 minutes, never.

Mark W from my iPhone

Thanks, Mark. So that’s the same as for me. Do your iDevices respect that setting? No early auto-lock?

I keep my phone set at 3 minutes, and it dims right around 3 minutes, then locks a little later. Let me try again at 5 minutes.

Set at 5 minutes, the phone dimmed a little before 5 minutes and locked right at 5 minutes.

There’s some uncertainty about how well I matched putting down the phone and looking away with starting the timer on my watch, but I consider both “on time” to the accuracy of my measurements.

I’ll try the same on my iPad and let you know if I get different results.

Mark W from my iPhone

Thanks, Mark! Sounds like your X is respecting the setting.

So then I suppose my 6 is affected by some kind of iOS bug. Not exactly what I was hoping to hear. I’m skeptical as to Apple’s eagerness to spend time fixing bugs related to “old” iOS hardware.

I did NOT get the same results on my iPad Pro (latest 12.9”). There, the lock delay seemed much less predictable.
Set to 5 minutes, still on 15-20 minutes later.
Set to 10 minutes, locked around 5-6.
Set to 15 minutes, locked around 7-8.

More testing when I get a chance, after a reset.

Mark W from my iPhone