I picked up my watch from o2, took out the data deal set it all up, when I leave my phone at home and a call comes through I answer talk for a few seconds then get a overheating message it shuts my call of and puts flight mode on, does exactly the same if I try to make a outgoing call, I'm at a total loss as of what to do, I've tried restarting it then resetting it but still the problem persists, I've checked to see if there is any updates for the watch but there is nothing.
I had this exact same issue today while trying to setup NumberSync with AT&T. Every time I tried to use LTE only (no WiFi or Bluetooth) the watch would overheat and go into flight mode. I did use it successfully for a few very short calls after this, but I am concerned about this going forward. I'm going to turn off WiFi and Bluetooth for the entire day tomorrow and see how things go.
First I'd try…
1. Soft reboot by turning your watch Off and On.
2. A reset of the watch
If this did not cure the issue and there are no available software updates to complete then I'd concur with @AgeofDarkness to consider returning the watch under any relevant Cooling Off Period to have it swapped out.
Daily Driver > Samsung Galaxy s²² Ultra 256Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I have no affiliation with Samsung.
Mine does this too. I am in the US and have the LTE 46mm watch 4 classic. Whenever I make a call it overheats, dims and goes into airplane mode until it cools. It usually happens within 2 minutes of the call.