Yes, it’s normal. As 4K UHD would cause a high load to the dashcam.
While please don't worry about it, there is a High-temperature Protection mechanism inside the cam,
A129 Pro front camera adopts heat discharge construction and the built-in sensor to detect the temperature of the main chipset. When the temperature of the chip reaches a certain degree, the device will automatically shut down to protect the dash camera from overheating.
If you still worry about overheating problems, we suggest you turn off the Wi-Fi, set the resolution as 2K during hot weather.
Also, we suggest you use the SD cards of Samsung, VIOFO high endurance series, which can work better with the 4K dashcam.