We had a mysterious problem in MOSS sharepoint portal in Tasks.
Following were the issues:
1. When ever a task is created; the alerts goes to people(some one in AD) for whom the tasks has not been assigned!
2. When ever edited also the same issue Plus the description will be striked & shown as such it has been changed.
3. When the tasks is deleted; the alert goes to the respective persons in the assigned to field and also to some other person in random!
Seems it is resolved in SP2 and there is also a Hotfix for the same issue.
Hope it helps...
This is My 100th post, Thanks for your continuous support :)