Well technically I think what you mean is "short circuited".
I have run buck pucks in parallel configurations quite a few times without any trouble. In general, you should be able to parallel most constant current drivers without any troubles. It is not a guarantee, but for a standard buck regulator, it would normally not cause any issues.
I highly doubt as many have said that the mismatch between forward voltages in the dies was an issue. If that was the case, one of the dies would have gone bad first, and the others would have gotten brighter till one of them died and so on and so forth.
The buck-pucks are in general quite efficient. While there is an efficiency improvement by having closer matching of the input and output voltages, even with 14V and 3.5V out, the dissipation in the Buckpuck will be minimal and while it may be warm, it should be no where near hot to touch at 700mA.
Now that said, the Buckpuck is only rated for 15 seconds short circuit. LEDs do fail short circuit unfortunately. I would expect that only to kill one die though and if it was shorted, in theory there is no current and hence no blackening of the other dies.
Going out on a limb (or taking some experience and knowledge into account), I would take a look at what was happening on the input to the buckpucks. You said 14V ....what were you using for that 14V? You imply all the buckpucks are dead? That is a bit unusual.
One last thing to consider is static electricity. Buckpucks are robust, but you hit it with a good static discharge and you could blow one. I do not know what the internal circuitry is, but if the internal switch fails on, bye bye LEDs.
Semiman