I have had a couple of occasions where the timer chime did not go off when the probe reached its temperature, but usually it works. However, the oven is not designed to hold the food at the probe temp when the oven temperature itself is set higher, which seems to be the situation in your case. (Oven temp at 175F and probe at 143F.) I don’t usually rely on the timer for notifying me of the probe reaching temp because even when it dings (which it does most of the time) it only dings once and it’s easy to miss. So I try to make sure I’m watching closely, either on the oven or, more conveniently on my phone using the app, and then I’m ready to pull the food as soon as the probe reaches its temperature. It’s possible the probe or the timer on your oven are not working correctly and you should contact support, but I’m not sure from your message if your probe was still reading 143F when you checked with an instant read and got 163F. If so, then it would certainly seem the probe is off. But it might be worth another try. Your screen shot only shows the temperature you set for the probe, it’s not displaying the probe reading, which shows on the oven handle and at the top of the app.