Now I have I noticed that I can be writing in a quick comment box and then it will stop typing for some reason. When that happens I do use the go advanced and use that to finish my comment before posting. But I primarily post here using IOS devices (iphone / ipad) and figured it was just an IOS thing because it never happens to me on a linux box or windows system.
Are you using an IOS device?
Have you cleared your cookies out lately?