See the top left of the photo; based on context this looks like a shared kitchen/laundry area of the unit. That’s what I was referring to.
As for caps - sometimes the caps are so flat that they sit flush with the ceiling, and if the ceiling is painted and the caps are not taped off or removed, it’s possible to paint right over it and make it look like it isn’t there. Not saying that’s 100% the case, but not outside the realm of possibility.