How must the middle purlin be sealed to the wall?

Hello,

our new building was completed in December. On cold days, we had the problem that condensation water came out on all four corners on the eaves side above the wall and then ran down the house wall.
Now I searched through my pictures and noticed that the purlins are probably "lying in the wall" without a vapor barrier.

This is how it looked from the inside before the drywall was installed. You can see that the vapor barrier around the beam is open:

[ATTACH alt="IMG_5503_kl.JPG" type="full"]43139[/ATTACH]

And this is how it looked from the outside before plastering (there was still an insulation board to be applied)

[ATTACH alt="20191012_184250_kl.JPG" type="full"]43138[/ATTACH]

My theory now is that the warm indoor air can rise unhindered through the wall here; it is only one stone height up to the roof. There, the vapor then condenses on the cold wooden board and runs down between the board and the wall.

[ATTACH alt="IMG_2580_kl.JPG" type="full"]43140[/ATTACH]

The drywall installer will come soon and open the ceiling again. What would be the correct sealing for such a wall penetration for the intermediate purlins? Does it have to be sealed all around with the vapor barrier? Or is it enough to foam the cavity between the beam and the wall? Or would the beam eventually rot then?
How is this done correctly?

What does the construction company say about it? The house is no longer insulated on the outside, right? Do you have a picture of the finished "outside"? If the first picture shows the finished state, the sealing is missing everywhere.

Layman's opinion, the vapor barrier + sealing is missing and they have created a perfect cold bridge. You probably already have mold behind the drywall inside.

The construction company hasn't said much about it so far, people are guessing where the water is coming from, and now they are just checking what the drywall installer has done. I don't have a picture from the outside right now, but it's simply a closed plastered surface. So towards the exterior wall, it's more or less airtight. but upwards through the brick, not really

No idea if all of this is professionally done. The pictures look like careless work. I would be alarmed as well.