I did change the inductor on the evaluation board to account for the higher current.
As to the rest - no, because none of the parts in the bill of materials would have been affected by the 2 volt increase, and on the output side it was closer, but still everything was good up to 25v.
This is only a 2 layer board.
The MP3428A hits around 150F.
The FET? I shut it down when it passed 150C. It would have happily gone into runaway at the rate it was climbing. Temps measured with a thermocouple and a Standford Research SR630.
This has to be some weird layout problem. I will probably try to copy the evaluation board layout more closely and try again unless you have some suffestions.
Thank you Cindy.