Samsung Galaxy S3, How to fix keyboard issues.(Backspace and L, Keyboard won't work)
1. First open settings.
2. Then open application manager.
3. Swipe left twice so you are on the all tab.
4. Find the app called Samsung Keyboard and click it.
5. Click clear data and push OK.
Your issue should now be resolved.
When holding the phone horizontally and trying to press backspace on the Samsung Keyboard it would type L, even if your finger was on the backspace. This issue also made the backspace key on the keyboard almost not work as the only region for it to work was to the far right of the key near the edge of the phone.