As a leader you should, in a productive and constructive way, name a problem if one exists. This might be a problem with somebody's behavior, it could also be a problem with a process. But, it's never good to just leave it alone and not mention it. By Stating It Once, you call attention to the problem, you put it on the table where people can look at it and you acknowledge its existence.
If you start to repeat the problem or are having redundant discussions about a person's shortcoming, you are starting to ruin their reputation, demean them and you are also not helping solve the problem. The best suggested thing to do is that after a problem has been stated once, which again is done in a productive and constructive way, it's time to change the discussion from problem acknowledgement to one of problem solving.
An example of accountability leadership stating it once is:
Your Manager: “I’ve noticed Phil isn’t coming through with his assignments on time … and it’s getting to be a real problem for me.”
You: “I’ve also noticed that, too. What’s causing it? Where have we failed to set specific timelines and expectations?” In pointing out that the failure may be on leadership’s shoulders, you’re looking into the mirror to find solutions.
State the problem once, eliminate redundancy, and move toward the solution.