Valdes charged up to his team-mate to complain and the pair ended up putting their foreheads together.
Boro boss Aitor Karanka said later: "It is not very nice to see things like that in the game, but I understand the frustration because we all want to win."
But Gibson remarked: “It shouldn't happen on the football pitch in front of all the fans.
“But it is not a bad thing as far as I am concerned. It shows people care.
“I would rather have that than nobody caring, if I am honest.
“Choice words, people arguing … I don't mind that. It shows they care. It is better to have that than people walking off without a word to each other, albeit it should be happening in a more controlled environment. Sometimes temperatures boil over and that was nothing. It was just a few words."