We’re going to be testing a fix for this in beta today, if you’d like to sign up for the beta we would love to hear your feedback and ensure it’s working. You can sign up for the beta here if you haven’t joined already:
https://play.google.com/apps/testing/com.jeremysteckling.facerrel
(note that it hasn’t rolled out just yet, I’ll update everyone once it has)
We’ve now rolled out this fix into our beta, if you’ve signed up you should see version 4.3.2 in the next few hours. Let us know how it works for you once you update! Thanks everyone!
I installed now 4.3.2_4471_beta-(4471)
I’m testing It
I unistalled app, reinstalled and reboot watch because only update app don’t solve issue
(remember to set C/F in watchface setting)
I’ll update here my test later
Thanks Gavin
Updated the Beta on Galaxy S8+ paired with ZenWatch 2.
I had to set to Fahrenheit and then back to Celsius, now it shows C since 10 minutes.
I’ll check every now and then if it’s finally fixed. 
C was displayed for about 30 minutes, now F is back again on the watch and in the app. 
After 3 hours it seems all ok.
I unistall app, reinstall app, reboot watch and re-sync face
Uninstalled everything and then reinstalled. Let’s see if that changes anything.
Okay, complete un-/reinstall did it: 2 hours and it’s still C.
@Falk.Wussow @acronimo5 Great to hear! We’ll let users know they may need to restart on the watch if they still have errors.
Thanks so much for your reports!
Ok for me Gavin, all the day in C!!! Wow 