This happens in any locale with a 24 hour clock format.
So, the root fix is to change the clock to a 12 hour format, make the
setting, then change the clock back to a 24 hour format. The schedule will
be as planned.
One quick shortcut to this, if you are not already on English (United
States) is to switch to that language (which has a 12 hour clock default
format) make the schedule setting, then switch the language back to your
preference.
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