Task Completed goal achievable by any contact?

I’ve been building campaigns under the impression that the Task Completed Goal can only be achieved by the contacts within the sequence that the task itself is in. I’ve built out processes that will perform an action after a timer if the user takes too long to complete the task, so that if they do then go on to complete it, it won’t matter which option they choose, the goal won’t be triggered.

I’ve come to find out this isn’t the case though and it seems counter-intuitive to me. I can see that there is an option to restrict the contacts who can complete that goal to be only ones who are in the same campaign, but no further to only include that sequence.

I’ve looked at ways that a task can ‘time out’ so that completing it is no longer necessary and it disappears, but that doesn’t seem possible either.

Any ideas?