A comment in the NAC-Matthew commentary (Craig L. Blomberg, p.321) says:
- Some textual variants reverse the order of the two sons' actions (cf. NASB), and a few change the leaders' answer so that they praise the unfaithful son. But the manuscript evidence is too weak to support this variant (limited to D, old Italic and Syriac versions, and not even noted in the NIV), despite some valiant attempts to make sense of it as the original reading.
The Westcott & Hort Greek text has the order seen in the older NWT. As I've noticed before, the revised NWT appears to make use of the UBS Greek and favor the differences in that text. (See here and here for other examples.)
Take care