My mother-in-law says the hand flapping is 'a sign of something'. Our daughter does it when she's excited

Whenever she's excited, she flaps both hands fast and squeals. Bubbles, her favourite song, my partner walking in from work. My mother-in-law saw a video on her phone and now brings it up at every visit. Daycare hasn't mentioned anything. She's walking, has a few words, waves bye, points at things she wants. I don't want to dismiss it, and I don't want to spiral either. Did your toddler do this? When did you decide it was worth asking the paediatrician, if at all? ❤️