The solution in this case is to update the ts_occur_date to a recent time in the ts_defects_interval table.
The MOM and collector running TIM Collection Service need to be stopped before doing this.
So an update to just before 9 a.m on 3rd August 2018 would look like this
update ts_defects_interval set ts_occur_date='2018-8-03 08:59:59.999+00' where ts_id=(select max(ts_id) from ts_defects_interval)
The date can be as recent as desired, but not a future date.
If there are defects in the ts_defects_interval table, they will not be aggregated, but new defects to come in after the chosen date will then be aggregated.