From Notes and Comments on Robert's Rules of Order, Fifth Edition:
Immediately. The member must make the Point of Order at the time of the violation. RONR (12th ed.) 23:5. The rationale is obvious. It would make little sense to rise to a Point of Order fifteen minutes after a speaker’s remarks to say that the remarks were inappropriate. The damage is long done. Robert’s even states that “if the chair is stating the question on a motion . . . that is not in order in the existing parliamentary situation, the time to raise [a point] of order is when the chair states the motion. After debate on such a motion has begun—no matter how clear it is that the chair should not have stated the question on the motion—a point of order is too late.” RONR (12th ed.) 23:5. As noted in Parliamentary Law: “After a member has finished his speech, it is too late to call in question the propriety of language used in the earlier part of his speech. After an amendment has been debated it is too late to rule it out of order, even though it is unquestionably not germane” (p. 150).
