Apple watch keeps score but it doesn't transfer all the strokes to iPhone

I want to leave my phone in the car while I play, but although the Apple watch keeps the correct score, when I get back to my car, not all the throws transfer, giving me a false (lower than reality) score to post. I know the advice is to carry the phone on the course, but the data exchanged is so small that it seems feasible to leave the phone. At one time, this worked, but no longer. Thank you.