Numbersync for AT&T has been on the fritz since mid July 2020 and possibly earlier than that. I own a gear S3 Frontier 4G LTE. Since July of 2020 my watch has not been able to maintain numbersync. I was constantly reinitializing the feature especially when I walked away from my phone. If I walked to the other side of my home the watch would lose its Bluetooth connection and if I stayed out of range long enough it would lose its numbersync. I started reading in forums about similar experiences. Not all of the experiences that I read about were exclusive to the Gear S3 Frontier. So I started to get some ideas about how to approach the problem. The first thing I did was to disable the watches Wi-Fi. That seems to work for me. I haven't had to reinitialize numbersync for several hours. Let's see how this works.
yes there is an update recently I spoke to a very intelligent customer service representative from technical support he convinced me that we needed to reset the watch. And I had read this somewhere else perhaps in this forum. the key to stabilizing AT&T numbersync is to reset the watch and restored manually. I did that and I tell you that my number SYNC feature is more stable and has been in months. when I turn the watch off I do have to check it when I turn it back on to see if numbersync is still engaged. but that is about it.