They were asked to advise -- give a general sense of the legality of the order -- by the Biden administration. SCOTUS said it wasn't legal... so the Biden administration is attempting to rephrase the old executive order into a new one anyway. They MUST know that it will be challenged and they MUST know the likelihood that it will backfire is EXTREMELY high... but here we are.
A colleague of mine suggested that this may be the impetus that drives Biden to attempt stacking SCOTUS when this obvious bullshittery falls flat. After some consideration... I think they, unfortunately, may have a point there.