Blur_in_mask issue, can't use specific mask?

Hi AFNI gurus,

Hitting an issue with afni proc, attempting to use a specific mask for BlurInMask, with the following line:

-blur_in_mask yes -blur_opts_BIM -mask ~/afni_global_dsets/subcortical_MNI152_2009_mask.nii \

But afni proc runs into a fatal error:

3dBlurInMask -preserve -FWHM 6 -Mmask mask_epi_anat.GM1008_subcort_ses-one+tlrc -prefix pb05.GM1008_subcort_ses-one.r01.blur -mask /home/dowdlelt/afni_global_dsets/subcortical_MNI152_2009_mask.nii pb04.GM1008_subcort_ses-one.r01.volreg+tlrc
++ 3dBlurInMask: AFNI version=AFNI_18.3.09 (Nov 27 2018) [64-bit]
++ Authored by: RW Cox
++ 1 unique nonzero values in -Mmask; 66579 nonzero voxels
e[7m** FATAL ERROR:e[0m Can’t have two mask inputs

I am doing this to limit blurring to subcortical structures, as I am doing cortical analyses with the surface pipeline and don’t want to blur in insula for example. Is there an option I am missing or perhaps specifying wrong? Thank you, as always.