I have had that very rarely with my iPhone (8+) I have never actually resorted to unlocking; just close and open the app and it works. Sometimes it takes about 5 seconds for the car to realize I'm there, too. Try the handle, does not open, try the handle again, it opens. Happens whether my wife and her phone are around or not.
More annoying, my charger frequently does not open the charge port pressing the plug button. Sometimes I open the back door and it works after the car wakes up. Sometimes I open the front door and it will respond. If I open the car and push the open on the screen, or use my phone, it opens. This is the third charger, so I don't think it's that.