My suggestion would be if its a custom scheduled task, to delete it and set the start date/time for some time in the future. Then be sure to set it to run on the schedule you're looking for. If your frequency is once per week, then
- set the Period field to Day
- set the Start time field to a time in the future on the actual day and hour/minute you first want it to execute
- set the Every field to 1
- check all the boxes you for the Days you want the task to execute on.
If you want to specifically execute it every Sunday morning at 2am, then your settings would look like this:
This should help resolve the issue you're having.