JL Audio f112 blown speaker?

sounds like a burnt voice coil, are you rolling off all your bass off your main speakers and your LFE to the single sub? This can sometime overwhelm a sub depending on the crossover level, plus gaming runs the sub continuously versus a movie.
Do you have your sub located in the correct place? are you pushing it hard but sitting in a null? Put the sub in your listening position and walk around the room where you might put the sub and place it in the loudest location. Then use the EQ to cut, because if you are sitting in a null you will keep cranking the sub and overdrive it.

The only other thing I can think of is that your power voltage is damaging the digital amp in the JL audio. What else is on that circuit? unplug everything on that circuit. tighten up the connections on all plugs and light switches on that circuit since they are wired serially typically. I had a an electrical that didn't tighten down the wires on the back and the + jumped off and was shorting on the back of the outlet. Be careful of live outlets!

I abused my F113 pretty hard with U571 before I sold it and it didn't even blink.

This is an amplifier problem or power supply problem in your sub. This is not good - especially if two units have done this. Perhaps JL have developed a QC problem with some parts they are using. Alternatively, if your Classe has a fault perhaps a high level DC or transients are reaching the XLR input on your sub and damaging the input buffers by over driving them. If your XLR cables are wired correctly none of the three wires should be connected to the connector or shield and all three lines should be isolated from eachother.

Make sure the connectors of your cables aren't touching adjoining cables on the back of your processor. Make sure your connectors aren't loose on your cables.