Help - flickering screen and other issues

Just got a brand new Ipad 3 just under a month ago from Amazon. Today when I was reading a book in iBooks there appeared a thick black line though the right hand side of the page. This got worse until the entire page was black as one progressed through the book. I turned off the device and later observed that the screen was flickering.

This device is not jailbroken, has not been dropped and is usually in a leather case.

My older Ipad 2 had no such problems. What is going wrong?

By turning off did you mean sleep mode or you restarted/rebooted it?

I mean sleep mode. I have since rebooted it and it is now working. Will this happen again? And why did it happen?

I'm not entirely sure it will happen again, maybe just a coincidence? Just hope it won't next time, and I don't know really know why, sorry.