I have a 3 floor townhome with trusses and a flat roof. I hired an insulation guy for flash/batt and noticed he didn't insulate between floors. When asked he and my GC said it's not required. I believe I am supposed to follow the 2018 IRC code, but it's so dang complicated you need a specialty engineer to understand it. Ultimately it will show up in my framing inspection, which I haven't heard back from yet, but my assumption would be that every space between interior drywall and exterior siding should have a layer of insulation.
It looks as though he didn't insulate between the 1st floor ceiling and the attic? That's not required. Generally only on exterior wall diaphrams, which would include roofs.
Consider air sealing on the interior?
It would not be required, however you have the chance at this point to do some soundproofing, if it is not already in your plans. Noise transfer floor to floor with trusses can be quite loud especially with hardwood floors.
I would think the truss area between floors on exterior walls should be insulated. With out it there is a gap in the exterior envelope. If you used a thermal camera on the exterior wall that area would show the hole in the exterior envelope.