It could be very well be a symptom of Specular reflection.
Specular Reflection is caused be the suns light reflecting off of the surface of the water.
When flying a drone over water with specular reflection, the drone's sensors can get confused...
Common problem with shooting hyperlapse, reported numerous times in DJI and other forums. Interesting video (link below) showing exactly the same slight left and right yaw... especially when shooting low-light or night. This slight yaw movement...
I tried timelapses of sunsets from my driveway with low winds numerous times, all with the same wiggles and jiggles. The drone is imply not as stable as a tripod and no matter what low wind conditions I encountered, and using warp stabilization...