Only if they do not maintain lawful status, which is what the law says anyway. In fact, it specifically mentions this: "USCIS acknowledges exceptions including nonimmigrant categories with dual intent and immigrant categories where only adjustment of status provides a pathway to permanent resident status"
https://www.uscis.gov/sites/default/files/document/memos/PM-...
Where in the memo does it say "only if they do not maintain lawful status"? there are plenty of people adjusting under employment based petitions who have non-immigrant visas (eg O-1) which are not dual intent.
Footnote 20 on page 4:
Footnote 20: However, maintaining lawful status in a dual intent nonimmigrant category is not sufficient, on its own, to warrant a favorable exercise of discretion