That's a bummer, still strange on all 4 like paul mentioned.
All of my Pman set modules are still working although I got them when already in builds.
Iv'e blown a few setting my own but mostly from my own stupidity.
The drivers don't seem to get hot, no where near the Aptlighting. It's just these modules are so exposed and so easy to short which I did quite few times by not having the right equipment. Pman first off sent me a set of little ceramic screw drivers because right of the bat I shorted a few by using jewelers screw drivers.
I didn't have the right alligator clips either and would use a battery box and just wrap the wires around what was needed and leaving them exposed
Iv'e set the amp's with 2 AAA's then power it with a 18650 or something
Iv'e also had quite a few successes and the ones I got didn't seem that fragile other than shorting them and like paul can't see all 4 fail.
They seem to come from the factory at .280mah and on a few the pot didn't let it go much higher than the .430mah but still they are working.
Did you have ESD strap protection?