Sorry I was being sarcastic hence the 
emoticon. I completely understand it’s a product characteristic and regen braking a 1800 kg car of a mountain heats tends to heat things up.
The manual theoretically states that the increase in traction battery energy isn’t displayed, but as we know, it actually does show up. The system likely isn’t designed for prolonged energy recovery, which is why this happens.
You’ll have to choose shorter descents