New Construction homes can have “issues” too.
In modern construction, all exhaust fans must vent to the exterior of the home. There was a time when some builders considered the attic to be “outside the home.” When we think about it though, is it really outside? Warm moist air being vented to the attic space can collect on cold surfaces causing decay/rot and lead to mold growth in the attic space.
I took the first picture inside the attic. One can clearly see two openings through the roof and two vent ducts attached to the roof sheathing below the two openings.

When I was up on the roof, I took the following picture.

It clearly shows the two vents at the top two openings in the previous picture. Where are the two caps for the ducts that attach to the sheathing at the lower locations? If these two vents go through the sheathing they have been covered over by the roofing. They should actually have been attached to the two higher openings.
How does this happen?
Hard to comprehend but it is yet another example of why it is important to get newly construction homes inspected.