Safari :: 5.1.2 Keeps Changing Text Field Randomly On Text Input

Safari keeps changing the text field on input, do you know how to correct this issue? 

Here is an example:

Let's say I load www.google.com, it appears in the safari window as usual.

Suppose I begin to type a search in the google search field at the top right of the safari window (not the one on the google page)

if when doing this the sentence is long for the search, at some point randomly, the rest of the text will be entered this time in the google search text field on the google page! (which is the very next text field) So when I hit enter it makes google search half of my request...

Safari changed the text field I was into with no warning. I want to say I do not press tab at any moment. This is annoying really, and this does not appear anywhere else than in Safari. It seems the issue is not systematic, but appears quite often. 

I have no universal access setting except "enable access for assistive device" I had to check this box upon installing a software in the past but I can't remember what it was.