I have also been getting this problem, and something that seems to work at the moment is to use the Accessibility Options in control panel and use FilterKeys.
In the settings select Ignore quick keystrokes, then in the settings for that under RepeatKeys set No keyboard repeat, and under SlowKeys, set to 0.0 seconds. Then use the shortcut to turn the settings on before playing and off when you finish.
This works for me, while FilterKeys is switched on movement is fine. Hope this helps other people.
Of course, if you need to delete something while typing in chat you'll have to repeatedly press the backspace key or delete key, but that's a minor sacrifice to be able to play the game.
