Several client machines are off (which explains why the scheduled backup is
missed); so I would not suspect the client itself. It looks that the server
is putting down a time-stamp by itself which is not related to anything
relevant.
Maybe a clue: what does the "Actual Start Date" mean when the schedule is
"missed" ? This applies whether or not it is before or after the "Scheduled
Start Date".

Gilles Danan