I have a watch 4 classic, and when I use facer, and the watch goes into AOD, the time will freeze until it wakes up again. This does not happen with the watch faces that come with the watch.
Facer only updates the ambient AOD face once every minute. It is normal for seconds to freeze until the first minute update then they will be a 00 and stay there. If everything freezes including the time it sounds like you need to get help from @Facer_Official on that one, you can contact them at: https://help.facer.io/hc/en-us/requests/new or email them at: firstname.lastname@example.org