Is that mold in the window roller shutter boxes?

I saw the following on the roller shutter box of 3 windows yesterday. Is this mold?

It is hard to see in the photos. But it almost looks like mold.

Looks like it. Cold, uninsulated roller shutter box --> warm air condenses on it --> mold. Since it is very small area and with a logical and easy to fix cause, I would say it is not further tragic.

Roller shutter boxes are insulated/[gedämmt]

Then they are poorly insulated or not professionally installed, in the 3rd picture you can clearly see the mold and condensation damage. Always provided that ventilation is done correctly.

Our site manager will come by tomorrow and take a close look at it.

It is ventilated 4 times daily for 15 minutes (cross ventilation)