Here's how I fixed sync issues with my LG V35:
If Surge shows as "Paired" in the BlueTooth screen on your phone, un-pair it, turn off BT and restart phone. Restart Surge. In Settings on the Surge, turn on BT Classic to "pair" and turn on phone BT. You should get a 5 or 6 digit number on the Surge that matches the BT screen on the phone. Click OK if needed, then turn off the phone BT again. Then start the Fitbit app and navigate to set up new device. The software will ask permission to turn on BT, click yes. Then you'll get the 4-Digit number on the Surge to type into the app. The rest of the setup completed without delay and it's worked for the rest of the day, capturing steps and heart rate.
