Keyboard damaged by overheating? Double letters..

Hi all

I have MBA 2012 and I have replaced my keyboard two time already. The second time the keyboard worked well for 4 months and then the same exact problem of the first one (lasted 5 years) appeared again.

In short when I type some specific keys (always the same) I get two letters on screen. E.g. if I type 'a' I get 'as'. If I type 's' then I get 'as' too. Such problem happens on key '1,2,q,w,a,z,x' (on US keyboard) and on some function keys like 'back delete' which activates the 'tab' at the very same time. Note that the problem can persist for long periods but it's not permanent. In the last two weeks since the problem appeared again, I had a couple of days where everything was working fine.

The problem is definitively hardware because everything works perfectly with software (I'm using it in this very moment) or external keyboard.

I suspect the problem is very connected to a high temperature of the CPU and I'm planning to replace in coming days the thermal paste.

Did someone experienced the same problem?

Many thanks!