3dbucket does not preserve affine info

Hi, AFNI experts
I am using 3dbucket to extract one volume from a functional dataset. Basically, I did
3dbucket func.nii.gz"[0]" -prefix vol0.nii.gz
I found that the output vol0.nii.gz did not inherent the affine information from mother dataset func.nii.gz. Not sure it is intentionally designed this way or a bug.
Maybe it is better to keep all header information consistent when using 3dbucket??