Status of "Restart required"

I'm migrating a lot of clients with AutoUpgrade tool. Everything worksk fine but the "Restart required" status reported appears as not correct.
I've a huge number of clients with the following situation:

In client status summary, I see "No" as Restart Required.

But if I check the client properties:

Other clients report, correctly, "Yes" in the summary.
Why does this happen? And how could I create a report that tells me exactly how many clients have the status of Restart Required?