Apple Watch 4 Companion - HR WAY off

For the longest time my Apple Watch never connected while using my iOS device running most recent versions (always) and using Zwift on MacOS latest versions. Now it started to connect and is showing a HR that’s about 1/2 my actual HR. FYI, I’m always using a HR strap that’s synced to Zwift so the actual HR being recorded/displayed on screen is accurate.

Any ideas of what’s going on or even if there’s any reason to leave the Watch app on the watch if I don’t use it for HR.

Oh, and when the ride is over it’s near impossible to get the companion app on the watch to end…even after forcing it off the Watch.