I-phone 7 camera appears to "blink"

My new I-phone 7 camera appears to "blink" in an out when opened and will not take a picture. It does this intermittently and in order to make the camera work properly, I have to swipe to "video" and then back to "photo." This is my 2nd i-phone 7 as I obtained a new one from Apple after a hardware problem was found, fixed and the camera still did this. Here is a video of the problem : https://drive.google.com/file/d/1nTgz4z8MseYT064KQ57qM9jkbyexOhtf/view?usp=sharing

Please help! I am losing my mind as this is the 2nd new phone. I also tried reading to see if this a feature of the phone but was not able to find anything.