Another happy camper with a Murata PQC250-12 installed.
It took a few resistor moves to invert the remote on/off signal and it took a bit more doing to get rid of very annoying acoustic noise whether on or off.
Spoke with Murata and one of the posters and no one has had this problem. I had it on the two supplies I tried.
It comes down mostly to one capacitor (ceramic, 10uF) that sounds like a dentist drill if you gently touch the top with tweezers. My solution was to replace it with a Murata metal mounted cap of same value. You can also get interposer caps. I first made my own interposer before the Muratas arrived by simply mounting the cap piggyback on a 1 Mohm 1206 resistor. I have to say that this was quite good.
If anyone want the on/off inversion info, I'll post it.