This is normal behavior, here is why: When the event table is
updated the information needed to determine if a schedule has
been missed or needs to be run is taken from the schedule
table. We compare the startdate/starttime from what is
in the schedule table to what is in the event table. If the two
tables have different startdate/starttime, then the comparison would
be useless in determing if a schedule has been missed or not.
Consequently, event table records with old startdate/starttime are
removed.

Tom Brooks
ADSM Development