Occasionally a task or two may not get finished on time, for whatever reason (monthly bookkeeping for example).

At present if I want to assign that incomplete task a new deadline date if can't be greater than the job's final deadline date. That's easy to amend obviously but if any of the related mail merge fields are reliant upon that initial job deadline date then amending it isn't really an option.

I agree there needs to be a warning in place when one tries to create a task outside the normal deadline but we should be able to override it should we so wish (i'd suggest it being an option toggle feature in Settings)