Aw, I think yan ay normal lang sa age na yan, a few of us moms noticed our babies doing repetitive movements like that when they're getting sleepy or overstimulated, kaya parang self-soothing mechanism talaga. Try lang maybe adjusting the position or gently patting her instead to see kung mas effective, pero if you're worried na may underlying issue or kung parang excessive na talaga, best to check with your pedia para ma-rule out any concerns!