The thermal pads are not missing. EVGA is adding more thermal pads in hopes of lowering temperatures for users at the users request.
The thermal issues in question are being experienced on ACX model cards, and EVGA is sending out thermal pads for anyone with an ACX.
This question has been answered numerous times on the thread you linked.
The sparking issue can not be directly linked to the heat unfortunately. As a matter of fact, we just had a power inverter catch fire at work and it wasnt even warm or in use. Electronics fail occasionally, it happens. Capacitors have caught on fire in the past, resistors have failed, traces have melted together... It happens.
The heat issue is new and EVGA is trying to help lower temps. The ACX and the ACX 2.0 functioned almost exactly the same as the 3.0 (except the 3.0 has lighting on them and a different shroud), and this issue was never evident. Hopefully EVGA can figure out what is causing the issue this generation, and if the heat and failed components are linked, they can resolve the issue for users..