If it is under warranty, then the manufacturer should be able to either fix it or get you another tablet.
The only things I could suggest would be to update the keyboard through google play (if it is for the whole tablet). If it is the one for the whole tablet (and not just one app) you might also try going to "Settings" and then "Keyboard" and make sure this is the main keyboard and not some secondary one. The google one should be the main one. Any others should be uninstalled and then reinstalled if they are the issue.
If however it is in just one app, then I would look into uninstalling and reinstalling the app. Just make sure you restart the tablet (turn it off and back on) in between uninstalling and reinstalling that app.