BEM mesh artifact

Hello MNE experts,
We have had difficulty with our current protocol creating our BEM
meshes. Specifically, our outer skin BEM surface layer contains a
strange artifact/error: large spiraling loops are created, which extend
well outside the head.

I am not sure exactly what information you need, but we ran the command
mne_flash_bem successfully (for subject SBT_MEG_002 in
/space/theta/1/users/Sarah/Stern/Subjects/).

In viewing the results with tkmedit we found the artifact.

Do you have any idea what could be causing this problem on that
particular surface?

Thank you for your help!
Thackery Brown