Why doesn't a Sallen-Key Butterworth Filter ring?
A Butterworth filter has a flat pass band (spectral response): -



But it will still ring when a transient comes along (time response): -



Only a critically damped or over-damped filter will not produce overshoot (ringing).



EDIED to show that a 2nd order Bessel filter does produce 0.433 % overshoot: -


Calculator source

The resistor value is manipulated to give a zeta of precisely 0.866 with Fd of 0.5*Fn (aka Bessel).