Watch bluetooth tethering problem

Whenever watch is about 50 feet from phone, it gets all confused and Siri doesn't work. It thinks it's still tethered to phone when the signal is weak, and it can't figure out that it should disconnect and use LTE. I can't do yard work outside my house unless I shut my phone off or put it in airplane mode. You'd think Apple would have tested this simple scenario, but Apple isn't what it used to be.