MPM3550E Low Load Ripple

One question regarding MPM3550E low load ripple.
We have design with MPM3550E where we apply 20V to the input and output set to 12V . With load below 1A there is huge ripple around 500mV .
is there any way to reduce that to minimum .
our design is basically based on EVM3550E-GLE-00A demo board and typical application from datasheet with 10uF on input and 22uF on output .

is there any way to force the module to do not enter low load/no-load mode ?