That seems messed up!
I'd prefer the metrics to be kCal but It did not make any difference when I swapped between Cal and Kcal.
iPhone, Watch app, My Watch tab, Health, make sure no drastic changes have been made to your health data.
Then force restarting the Watch and paired iPhone at the same time:-
Force restart the Watch
i.e. p ess and hold both the side button and Digital Crown for at least 10 seconds, then release both buttons when you see the Apple logo. Then while Watch is restarting,
Force Restart the paired iphone Force restart iPhone – Apple Support (UK)
You may also want to make sure the software on the watch and iphone are both up to date to the same level. Updates are in pairs. eg iOS16.4.1 and watchOS 9.4 go together
Update your iPhone or iPad - Apple Support and
Update your Apple Watch - Apple Support
Test it for a while. If it is still misbehaving...
You may or may not have done this
Calibrate your Apple Watch for improved Workout and Activity accuracy - Apple Support
then
Unpair and set up again
Unpair and erase your Apple Watch – Apple Support (UK)
and then set up again - takes about 20 minutes
Set up your Apple Watch – Apple Support (UK)
If necessary unpair and setup without restoring the backup
If you've completed that troubleshooting and the issue is still not resolved, Contact Support.
Click here > Contact - Official Apple Support
or phone numbers
Click here > Contact Apple for support and service - Apple Support
and or Genius Bar Reservation and Apple Support Options - Apple
