Got your board, indeed it had the behavior you described, the SHUTDOWN LED was ON as soon as the board came ON, sometimes flickering. Very strange and I've never seen this before.
Although the solder job looked ok from below the board, lifting the plastic spacers of the headers reveals a really nasty suprise.
There was a TON of flux and some strange residue between the PCB and the headers, hidden by the plastic part.
I removed the headers, cleaned everything up, added new headers, now everything works as expected.
So lesson to take home: not sure what solder you used but cheap solder that has tons of flux in it can cause shorts, corrosion and other problems.