Further interesting information:
In the Admin UI, under Class of Service, Default, Advanced; the options for Authorization Toke lifetime and Session idle timeout have hours and days in the drop down selection.
If I go to Account, anyuser, Advanced: the drop down select has days, hours, minutes,seconds for choices.
On a hunch, I set four different users with four different times:
The user with 12 seconds could log in and then would be immediatly logged back out.
The user with 12 minutes could log in and then, after about 1 second, would be logged back out.
The user with 12 hours could log in and then, after about 1 minute, would be logged back out.
The user with 12 days could log in and then, after about 10-12 minutes, would be logged back out.
Using the zmprov ga user@domain command, all users showed the correct zimbraAuthTokeLifetime ie, 12s, 12m,12h,12d.