Is that mold in the window roller shutter boxes?

That can almost only be an installation error. Ventilating 4 times a day is more than enough. Just don't let the site manager downplay it by saying you need to ventilate more.

Roller shutter boxes were opened, everything is okay inside the boxes. Everything is dry, no strange stains or anything else. Also, at the window where that was already on the wall, now someone is coming to take a closer look at it. Our site manager said that one consideration would be to retrofit window frame vents since we do not have controlled residential ventilation; what do you think about that?

No mechanical ventilation is already a defect per se.

No forced ventilation is already a defect per se.

Pub talk.

Technically, of course, it is not correct.

yes, forgot the " ". I still can’t understand how something like that can be overlooked in the planning, even if it’s just a window rebate ventilation.

Can also be incorrect ventilation in the form of permanently tilted windows. Lintel/frame cools down, humid indoor air condenses precisely there.