Shouldn't it know when my planned contributions to Goals end?

Let's say I set a goal to save up $2000 within the next 4 months. It would calculate and let me know that I need to contribute $500 a month. I say ok. I can look at this month's budget and see the $500 gap. I can choose to allocate $500 for this month a future month's toward this goal.

I flip to next month - yep, I see the $500 allocated. Next month, yep. Next month, yet. Next month...wait - why is $500 still allocated? At this point in the future, the goal would have been reached. No more need to allocate.

Is there something I'm doing wrong?