[Intense Soul]

The device flicks and displays Apple logo and auto locks itself. Anyone facing this issue. I see this once in two days.

[Just_Me_D]

No. I've never experienced anything like that. Anyway, when you say the "device flicks", what specifically do you mean? Also, what do you mean when you say it "auto locks itself"? Are you getting a disabled prompt?

[Intense Soul]

What I exactly mean is, if I'm opening an email or browsing apple website or any website, or chatting with someone on iMessage sometimes the screen displays Apple logo all of a sudden and gets locked by itself. It's like annoying in middle of the work.

[SwitchBeach]

Are you saying the the device is randomly rebooting?

[Rob Phillips]

What I exactly mean is, if I'm opening an email or browsing apple website or any website, or chatting with someone on iMessage sometimes the screen displays Apple logo all of a sudden and gets locked by itself. It's like annoying in middle of the work.

What do you mean by "getting locked"? Are you saying that it's rebooting to your lockscreen where you have to enter your passcode?
If that's the case, go to Settings > General > Reset > Erase All Content and Settings. This will bring your iPhone back to factory defaults. I recommend setting it up as a new device to minimize any software problems but you can try restoring from a iCloud or iTunes backup as well.

[Intense Soul]

Yup getting locked and I've to enter passcode. But it's once in two days.

[Rob Phillips]

Yup getting locked and I've to enter passcode. But it's once in two days.

So it's only happened once, or it happens once every two days?

[Intense Soul]

Once in every two days mate!

[Intense Soul]

Update: Anyone facing force close of web browser when browsing shopping sites.

This is another issue started when browsing sites with many ad ons including mobile nations.

[H3aTeRzz]

Sounds like the equivalent of a springboard restart, not full power off. Weird. Maybe try Clearing Partition Cache, and if that doesn't help...you guessed it, factory reset, restore as new. J

EDIT: DUH....so used to giving that advice for Android (clearing cache) lol! Anyway..try doing a hard reset, then maybe a "Reset all Settings" under General>Reset

Hope this helps.