I am having exactly the same issue. I have reset the watch and the phone but it has not resolved the problem. Everything works fine until the watch and the phone are parted. The watch then gets almost too hot to wear and then goes onto the cooling mode.
Other than turning off the independence feature what can I do?
I recommend having the watch evaluated by a certified technician. I will be happy to look into your options. Please send a private message with the full model code and the serial number or IMEI number of the watch. http://bit.ly/2XERsky