If it's completed why does that matter? Is it a repeating task?

Yes, its important only for repeating tasks. At the end of the day i check tasks i postponed that day (priority:1 AND isSubtask:false AND postponed:>0).

Gotcha. The reason this happens is because repeating tasks are essentially considered to be the same task (technically a "task series"). So they keep all of their attributes such as number of times postponed, notes, etc.

However if you were to use the repeat "after 1 week" instead of "every week" a new task would be created and reset the number of times postponed. The disadvantage of this is a new task is not created until you have completed the existing task.

When you use the "every week" a task is automatically created every week whether you complete it or not.