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.

O-1 is a dual intent visa, as is L-1, as is H-1B, so I have no idea what you're talking about?

No, the O-1 is not officially dual intent: https://www.wegreened.com/o1-visa

Complete nonsense. It is.

https://fam.state.gov/fam/09FAM/09FAM040213.html#M402_13_5_B

Do you know why many sources state that it is not dual intent or that it is "quasi dual intent"?

"The noncitizen may legitimately come to the United States for a temporary period as an O-1 or O-3 dependent nonimmigrant and depart voluntarily at the end of their authorized stay and, at the same time, lawfully seek to become an LPR of the United States."

Seems extremely clear to me.

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