I currently use a lock code for my device and when i double-tap on the power button, the phone use to lock. When i would press the power button once to unlock the phone i would be presented with the number keys to input code. However, today i have found that the phone does not lock, when i press the power button to unlock the phone it goes straight to the desktop. I only found out about this because I had the corded headset connected to the phone when i put it in its case and in doing so i heard the touchscreen presses. I understand that magnetic cases can wake the screen, however, when locking the devices and then waiting a few minutes, i unlock and boom, right to the desktop. The only times it seems to unlock is if i wait the alloted time for it to autolock, which is 10minutes. This was not a problem before update i can assure you. Anyone else?

... are you using "secure device" or "lock screen and keys"? ... each has a different function!

thanks for that, at least now i can lock my device when i want using that method. (i actually forgot their was a difference)
However, i still cannot secure the device by double-tapping the power key like i use to.

i have rebooted the device and also done a battery pull

Go through the settings again, I think there's an option for that, secure device on lock or ask for security on unlock.

I might have a flashback from another OS though.

EDIT: Settings > Device lock > Autolock.