I also have a Mission Control issue with a Wahoo chest heart monitor. The strap connects to Mission Control and pairs correctly. One can see that there is a current BPM reading in Smart Control and at the end of the ride 'my ride" data shows average HR as well as Max HR.
However, when I am riding, I can't get a current BPM reading when that is selected on one of the the Stats drop down menu. I got the bike last fall and it worked fine until about three months or so ago.
Specialized support suggested getting the Wahoo strap as opposed to the one I bought on Amazon. That did not make any difference. I have tried all of the various connectivity suggestions in this forum.
Does anyone else have this problem? Iphone 11.. Strap is Bluetooth and Ant+ compatible.