If a task is completed ahead of the actual deadline, the time by day should be adjusted to ensure no future time is still planned and/or that task should be removed from still showing in the resourcing tab and suggesting someone is still working on that action.
Example below: 5 hours allocated for "Develop document" and allowance of 5 working days (M-F) to complete giving 1h/day resource allocation. If the action is then marked complete on the Wednesday, the 5 hours would automatically move to fall M-W, with Thursday and Friday then being clear of all hours assigned.