I'm having this particular issue (my cursor moving backwards randomly when I'm typing) since I bought my Mac (MPB13 mid 2012). It doesn't matter the application I'm using to write something down, it always randomly moves backward at some point. For instance, I'll be writing "if you're|" (where let's say | is the cursor showing me what's the last key input) it will jump directly backwards and it will be like this "if you'r|e" so whenever I keep typing everything I type will be between the r and the e in "if you're" instead of following the last word. Is very frustrating because I always have to relocate it so this doesn't happen and for me to keep writing normally. Does anyone experience the same problem? I hope I managed to explain the issue correctly.