Hello Ankur,
May you please explain how you are measuring the output? We recommend using a spring ground probe tip or a very short ground loop on your probe to minimize noise pickup. Measurement point should be made directly on the output capacitors as well. Are you also using full bandwidth on your oscilloscope?
You may also further contact the MPSNOW team at mpsnow@monolithicpower.com if you would like to deep dive into the smaller details.