Glad I am not the only one. Have F6 Pro and going through same thing. I emailed tech support received the response that they are working on it and should have an update soon. Just started for me last week after the updated app.
Just to add - I did have to switch Bluetooth off and on again, but at least that is less painful than having to set Vivosport up after every reboot....
Same since the new update last week. iPhone 8. Current iOS current garmin app. Randomly, first open of the day I have re setup my watch and 810. Watch is easy. Edge 810 pain in the butt.