glori3

But... nothing about “12am” sets that expectation. You need to know when they started work.

If you did, do you get fired? Genuinely curious: what happens?

Personally I strongly prefer no fixed working hours. If you want to work at night, so that you can do things when it’s light out (especially in winter), and you still get the expected results, what’s wrong with that?

It’s perfectly reasonable to work at 12am, and there’s nothing in the parent comment to suggest that they’ve been working since 9am or so. Maybe they started working at 8pm. Modern work should be asynchronous. If your company cares about butt-in-seat time, it’s the one that’s wrong.