Ytong adhesive applied too little - Is this a defect/to be fixed?

Yes, that it could draft, cracks could appear later, that these are mold-prone thermal bridges or the soundproofing does not fit. If I were a professional, I probably would not have asked.

The plaster makes it sealed. We have exactly the same construction, also Ytong, also with smaller or larger defects. But we have lived in it for a year, nothing leaks, zero mold. Really.

Don't worry about it, the Nordlys sometimes has its glitches in the heat ;). At the core of his statement, he is right though. Raw builders are coarse motorists and work accordingly. But that's fine, you don't need to worry about that and the plaster makes the house airtight.

Aha, thank you for your answers.

Be glad if there is a lot of air and little glue inside... air is the best insulator after all ;)

With butt joints, that would not be a problem. But here it concerns bed joints, so more about structural strength than tightness. The adhesive is supposed to distribute the load. In this condition, the wall is less load-bearing. From my point of view, a defect.