what causes these rippled lines?

My VC3-500 has a Duet 3 6HC. I have 9 x 9 mesh BL. Max error is like 0.2mm. I have an issues with curves. Especially large ones printed fast. The extruder makes a sound almost as if it’s stuttering. Print acceleration is 2500mm/sec3. Rest are: M201 X10k Y10k Z100 E5k (mm/sec) M203 18k Y18k Z800 E5k (mm/min) M205 X8 Y8 Z0.4 E5 (mm/sec)