In question, under discussion; also, to be decided. For example, Who will pay for the refreshments was the point at issue. [Early 1800s]
In conflict, in disagreement, as in Physicians are still at issue over the appropriate use of hormone therapy. This usage, from legal terminology, was defined by Sir William Blackstone (Commentaries on the Laws of England, 1768), who said that when a point is affirmed by one side and denied by the other, "they are then said to be at issue."