We have to put up with these fights every single day, at least once. Usually it happens in the middle of the night and I have to wake up to break it up.
Rey doesn’t just climb up the gate. In fact, he usually climbs up further to the left where the plants are. By doing so, he thinks he is camouflaged and can launch a stealth attack on Samantha.
Perhaps it is Samantha who mocks Rey and that causes him to retaliate by scaling up the gate to yowl at her?
We will never know.
But the fights go on….every single day.