When entering a Negative Wall Stock value, it is not being honored, instead only cutting to the wall of the geometry selected.
This is working as designed. The option of the Exact Positioning toggled ON is causing this result. Toggling OFF the Exact Positioning will now allow for the Negative Stock to be removed.
Further information can be found in the Documentation:
https://docs.sw.siemens.com/en-US/doc/209349590/PL20230425446868577.mfgmilling/xid457331