Thermostat overheating? (The device itself)

I have just installed the Tado thermostat, bridge and a few knobs, but this issue is something I have a hard time finding info about.
It's 48.5°C at the thermostat, doubtful but when I touch the device (button) it's fairly hot to the touch. Any suggestions?
It's a 2 wire setup. Black on -, white on +.
https://photos.app.goo.gl/GQuyPS5pCJ3HaPmz5