Hi, firstly I have to re-boot my watch when attempting to connect my chest strap. It would take ages to connect, I even bought some conductive gel to see if that helped but no. The watch needs to be shut down and restarted before the strap connects to the watch straight away. I have an old polar strap same problem and even with a new soft strap same issue.
My earphones connect no problem and at first thought they might be the problem, so would wait to connect them last, nope still no better. Another annoying problem is the earphones cut in and out for the first 10/15mins of my run when using my watch for music and using the chest strap. I had been using my phone for music for the last couple of months as I needed it with me due the lockdown. I had thought that the spotify playlist hadn't downloaded correctly so deleted and reloaded it, no joy.
So question; is this a known thing or is my garmin heart rate module interfering with the watch. Now it broadcasts Ant+ and the earphones use bluetooth so in theory shouldn't conflict with each other. It's a very annoying problem as the music stops and starts and pace info cuts in and out, the reason I bought the watch was that I could listen to music and podcasts without the phone. I had started a heart rate training program with garmin and so began using the strap again to get a more accurate reading.
I don't mind the restarting of the watch, it's only a couple of button presses and a few seconds but the music cutting in and out is really annoying and means I need to bring my phone with me so might as well have bought a non music version. I did email support but no answer.