You may have an alarm set for 7 days and have it send out an alert even if the parameter was not set.
The date may show correct, but the actual time may be over 7 days, which means the alarm is in fact correct
For example you may have Spotlight trigger an alarm for weekly database backups if no back up was made for 7 days. It got raised at 1:59AM on the 20th, 7 days and 47 minutes after the last backup was taken, which was taken on the 13th at 1:12 AM.
Try upping the threshold for your alarm to 8 days if you are doing weekly backups. That gives a bit of leeway SQL Server scheduling. If it tried to backup and fails you should get a backup failed alarm anyway within 5 minutes of the failure. This alarm is just to warn when your most recent backup is too old.
