Clever of you to get that far. You're missing a registry value that's required called bSchConfigChanged.
Set this to 1, and the task will be flagged as "I need to be rescheduled!"
The downside is, if this value remains in your GPO then every time GPO is enforced and it writes the value then the task is going to be rescheduled _again_. That may cause you problems long-term. Using ePO is the better choice.
Thanks, works like a charm.
Maybe i'll write a little script that compares the registrykeys to set bSchConfigChanged to 1 or 0.