Apple Watch timer freezes between 22 to 19 seconds.
I use the 3 minute timer three times each day when taking eye drops. In more than half of the occasions, the timer freezes with 19 to 22 seconds left. It stays frozen until I move my hand, and if the 19 to 22 seconds have passed, it alarms. Model A2094, version 8.6.
Apple Watch Series 5, watchOS 8