problem with schedule tasks

Hi,

just started to work with collection updated from AD and it works great!
other admin update the securty groups, and altiris update the collections.
problem is that the schedule tasks don't update the coputer list that they should process
with the new collection data!

to update the schdule task i need to delete it and then create it again.

couln't find any thing in symantec KB....

help!

thanks...