How does the Bluetooth work? Does it make contact with the camera or with the phone? it seems to be a hit&miss do you press button once or do you give a long press till you get a response
I had a similar problem with a Nextbase when in Spain 27c so I directed the AirCon to windscreen which seem to cool it down. Having just bought and fitted the A139 I did find it was getting a little hot even after less than 1 hour guess only time will tell. Without looking does it have vents...