First time I've heard of this one. Not sure if these suggestions will help but give them a try if you haven't already.
Go to the Home screen and double click the Home button. That will reveal the row of recently used apps at the bottom of the screen. Tap and hold on the app in question until it wiggles and displays a minus sign. Tap the minus sign to actually quit the app. Then tap anywhere on the screen above that bottom row to return the screen to normal. Then restart the app and see if it works normally.
First thing to try is a reboot of your iPad. Press and hold the Home and Sleep buttons simultaneously ignoring the red slider until the Apple logo appears. Let go of the buttons and let the iPad restart. See if that fixes your problem.
Like any computer there are occasionally errors that pop up. Rebooting the computer often helps. Seems to be the same for the iPad. I have to do this with mine every once in a while but not often. I use my iPad every day and never turn it off. It only sleeps when I'm not using it. Seems lke once a month or so, maybe even less often that that, I end up doing a reboot. Perhaps some apps are not written well enough and they cause problems I just don't know.
I'm glad the reboot fixed your problem.