Hi,
No, we stopped testing on flash since we realised Unity didn't really care about it. If this is on an old version I could take a look I guess, but I don't have a flash license. It might be worth checking the ListenForKeyboardTextUpdate() function in that file, specifically this line -
string inputStr = Input.inputString;
...
c = inputStr[i];
...
newText += c;
change = true;
Unity could be doing the wrong thing there. A couple debug.Logs will give you an idea of what the values are before it gets fed in.