I’m taking this issue to the manufacturer among other departments. But I will share here.
The line voltage thermostat is using 12 AWG stranded wire with soldered connections.
The product is listed for 5280W @ 240V, 22A
Don’t know how this was approved. The product has 5263W @277v , 19A. Only then may this thing not cause a fire. 
This thermostat was connected in accordance with manufacturer’s installation instructions.
The load was well below max wattage. (4000W) You can do the math.
The wires started to melt among other things the product was used for less than 2 months.
There is a YouTube video of another thermostat that had significantly more damage.
So here is my biased product warning 
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