GT-N5120 Lockscreen Freeze & Reboot

I bought my GT-N5120 device just over a week ago and have set it up, installed apps etc without issue. However, this afternoon, I opened the sleep/wake cover, my device's screen turned on at the lock screen as usual. I then swiped the screen to unlock and nothing happened. For information, there was a frozen looking ripple effect on the lock screen, but this did not move/animate as it would do normally when unlocking. I swiped the screen a couple of times and then the device's screen went off, the Samsung boot animation displayed accompanied by its sound. The device then rebooted.

It seems OK now. This is the first issue i have experienced with this new device. My question is: is this likely to be anything to be concerned about?

Software version is stock, un-rooted 4.4.2.

Thanks in advance :)