If you receive a push notification or the camera display saying that the device is overheating. It means your device used a lot of power and get overheating. The AiCam app monitors actively the device temperature and precautionary pause running if the device get hot and resume running when it is cooler. If the device is stopped running because it is hot, it is still under the allowed temperature limit defined by Apple. If the device is hotter than the allowed temperature defined by Apple, the OS will show a black screen with a red thermometer and the device is not useable until it get cooler. It may be annoyance that the app cannot monitor for events, but it will not impact the hardware as you can still open and use other apps.
The overheating problem may occur with older models like iPhone SE (1st gen) because they do not have much compute power required for running AI algorithms. You can do the following to avoid overheating on your device: