I think you’re right about it having to do with connecting to Bluetooth at start up. Sounds like our experience is similar. I had it fairly frequently for a while then it seemed to go away and now it’s back. Sounds like a software issue that hopefully can be fixed with an over the air update at some point. Also, sounds like our OCD is similar lol.I too had it on a regular basis about 6 months ago and it went away. It has returned more frequently one the last month or so. I think it has to do with connecting to Bluetooth at startup but not sure. If I hit cancel which flares up my OCD it works fine.
At the same time my Amazon Music through Apple Car Play will sound tinny until I press on the App on the screen now as well.