I found an issue with the timer after the 6 UI update.
When resetting the timer with a Galaxy ( 4 classic and 6 classic) watch for ~10 minutes the phone will say the timer is reset but the timer does not restart.
The timer will restart from the watch for short times like a minute or less. The timer can be reset from the phone with no problems.
Before the 6 UI update the timer functioned normally.
It appears that there's a timer issue on the Galaxy 4 Classic and 6 Classic watches following the 6 UI update. When resetting the timer on the watch, it doesn't restart properly after approximately 10 minutes, although it works for shorter durations. The solution may require a software update to address this timer bug, as it was functioning normally before the 6 UI update. In the meantime, you can continue to reset the timer from the phone until the issue is resolved.