Is the teacher really singling them out, or are kids misreading the situation? You weren’t there to know. If you tell kids to just work it out with the teacher, they may think you’re not on their side. If you run to confront the teacher, kids may think you’ll jump to the rescue no matter what the situation.
Talk with kids about how they can approach the teacher. (You can always intervene later.) This way, kids know you want to get to the truth and you’re willing to help. But they also get to be part of the solution and learn how to