Actually it's not fully correct to say 'маленький и легкий чайник' instead of 'маленький легкий чайник' because in the first case it can mean two kettles - one small and one light. So и is definitely not required here.
I put "Tim always takes a small and light kettle along with him". That is what it says in Russian. Why would it be marked wrong and corrected to something an English speaker would be less likely to say to express the same thing?