I overheard my son’s teacher saying he has “crackhead energy”

My son started preschool for the first time a few weeks ago. He is a very active and energetic little boy, always talking, laughing, wanting to run around. But he is also so sweet and affectionate. On Thursday I went to go pick him up from school and I was walking towards them on the playground. His teacher’s back was to me. I saw my son running around in circles around the swing set laughing. As I approached his teacher she was talking to another one standing beside her and I heard her clear as day say “Josef has crackhead energy” and laughed. Josef is my son. I stopped in my tracks and I was like “what did you say?” She turned around and saw me and her face burst into a big smile and was like “oh hey! Josef has had such a good day!” I was like “did you say something about him just now?” The other teacher looked uncomfortable but his teacher was like “no, we were just talking about a movie” and looked confused. But I swear I heard exactly what she said. I didn’t respond and just took my son and left. Tomorrow he goes back (it’s been a 4 day weekend) and I’m honestly still so upset by it. What should I do? Confront his teacher again? Talk to the principal? I feel like it’s just going to be my word against hers.