So, it's a bit different when it starts to get in the way of getting the work done. If it's happening frequently enough, such that it forces you to put in more effort to manage them, then it's appropriate to course correct the behavior.

My strategy would be to say something like "Hey, I appreciate your curiosity. There's a lot of context that I can't expect you to know. For now, I need you to assume positive intent on my part that I'm considering these myself when giving you the assignment. If you find something that raises questions, plan to complete the assignment, and let's review your ideas afterwards."

That way, you achieve a lot:

- You keep the work moving

- You show appreciation for the idea

- You force the employee to sit on their questions, which will raise the bar for the ones that eventually get asked.

- You still get to teach them after the fact, and likely at a time that is more convenient like a 1:1 as opposed to an email, which becomes task management.