Brown holes/spots on new calcium silicate brick wall?!

Hello dear community,

Our newly built wall suddenly showed stains and holes that look like rust or burn marks. This is both on the interior and exterior walls.

The entire walls are affected, the photo shows a close-up detail.

The shed we are talking about here is roofed but not enclosed.
We cannot explain these damages - we consider efflorescence unlikely because calcium silicate stone is not a natural stone. The wall is exposed to wind and weather on the outside, but not on the inside.

Does anyone have an idea what this is?

Best regards,
Janine

Another shot from further away please, to see the component.

At first glance, that looks like rust. Is there steel in the drill hole?

Hello Alex85,

There are no drill holes - the damages appeared all of a sudden... attached is a larger photo.

Best regards,
Janine

Doesn't anyone have an idea at all?

Best regards,
Janine

But, rust

And where does that come from? From the inside? Is that some kind of efflorescence and if so why? Those are not screw holes or anything like that. The wall was erected and has been standing there for 3 months now.