KfW 55, Ytong 36.5 poorly glued, too much gap?

Yes, still air insulates heat better than stone. Additionally, the joint proportion in relation to the stone is extremely low. Various stones are hollow inside or have gaps.

We just had that, ...

The butt joints should not be wider than 3 mm and do not need to be mortared. Butt joints wider than 5 mm must be sealed with suitable mortar.

Not comparable, because we build monolithically. In the other thread, there is still an [WDVS]....

But willo has the perfect answer... I can live with that....

That is normal and happens everywhere. No panic. Looks strange... but it is correct.

--> "unmoving air insulates heat better than stone"

Hello,

...Am I correct in understanding that if the stone is not completely glued, the insulation value drops significantly? The stones are not properly connected... horizontally nor vertically....

This is poorly executed. Only the bed joints (horizontal) are glued. The vertical joints are joined flush without any gap (butt joints). Therefore, stones with tongue and groove are used.
It is advisable to study the manufacturer's processing guidelines.

Best regards.

I am puzzled that you can actually see through the vertical joints. So there is no interlocking there? But for me, it is more about the mechanical stability; the insulation is probably fine, as others have already mentioned. I would also like to have the technical documentation of the bricks handed over.