The default zfp compression level is 11 and usually it works fine without noticeable defects. However, in some cases (I am guessing it is related to the distribution of NaN pixels which are common in the moment 1 and 2 images (velocity field and velocity dispersion) defects are visible such as the following example which is a moment image (velocity field).

compression=11

compression=32

@kswang1029 should perform more experiments to see if we need a refined default compression level.