This is a rubbish position that will ruin productivity. Rather than raising an issue, when I work on an unrelated task you think I should investigate instead?

This is a rubbish position that will ruin productivity. Rather than raising an issue, when I work on an unrelated task you think I should investigate instead? That's how unplanned work happens, and productivity drops. Problems should be raised, and prioritised, if it impacts the current task and prevents completion then it should be worked on. But as a manager you need to be aware that there is a problem and that it will impact timelines. If it does not impact the current task then there needs to be a business call on the priority, and if the worker should drop the current task to resolve it. Sometimes the worker has the experience to know when the issue is a business priority, but I have been caught out before when something seems important but promises have been made on the original task that were not communicated raising the priority. Communication isn't a bad thing, and not investigating is also not a bad thing.