Let's not say that the null check leads to a full table scan in high load scenarios. We only know that one user had this situation and query execution (across all our supported databases) depends on more factors than the presence of a null check
Let's make the users aware of the fact that jobs created before activating the flag will not be picked up by job acqusition, unless they explicitly set a due date (e.g. via API)
Task
L3 - Default