So far I have noticed a couple things that could be problems. When entering text the cursor skips back a few spots on its own causing your entry to be incorrect. Also when sending a text msg, the last character entered in the msg is repeated after the msg is sent, starting a new msg.

Edit: The cursor skipping back seems to be only happening when entering a character other than a letter or number. When these characters are entered a cursor actually shows under the entry and if you do not wait for it to go away it will mix up the letters.