My stab in the dark is that a wire common to the three non-working lights has come loose. You may need to dig into any paneled area accessible by removing screws to see how the wiring is configured.

Thanks! The area is pretty tight but perhaps an appliance repair guy who has worked in range hoods could find that loose connection or damaged wire though I don't know what could have caused either issue.

I have the same issue, all went out at once, flickering a bit now, but issue is not apparent.

Did anyone ever get this resolved?