In am using the "refine radius" tool in "refine edge' on a mask. Instead of adding in the missing parts, as is shown in the tutorial, it adds an edge, but deletes contect from both the mask and the original file.

I am trying to refine a selection on a mask using the refine edge panel, and inside that, the refine radius tool per the tutorial on Creative cloud. However,it just removes the content from both the mask and the original! Help!