It’s something to do with printing small circles. My A1 does the same, maybe not as extreme as yours, but its definitely louder when printing small circles. I did try to look into it online and the result was something to do with polygons or something in the model - didn’t quite get it, but Bambu came back and stated it was normal.
My Prusa MK4s doesn’t do that though - that runs much quieter than the A1.