Starting a ride with a heart rate sensor (whoop band, bluetooth) it is 50/50 whether it will connect automatically or not.
If I see it hasn't connected, I can go to the sensor list and see it is "searching". Select sensor, hit connect, immediately finds it and connects.
This would suggest that the status of "searching" is not correct as when you manually tell it to connect, it does immediately.
I don't see how I can set it up any other way to connect reliably. It's there, it's broadcasting and it connects when requested. It just doesn't always connect automatically.