According to findings in the Senate Judiciary Commitee (not from Trump's mouth):

"As of August 21, 2017, 45,447 DACA recipients have been approved for advance parole through an I-131 Application for travel documents. This approval allows a DACA recipient to travel out of the country and legally return, making them eligible to adjust their immigration status and receive a green card."

In other words, they're gaming the game...