Cracks in the window lintel/clinker - How to act?

The masonry lintel of this formwork is not executed professionally

Please explain. How do you recognize that? By the rise? The opening width? Or does something not comply with DIN 1053? Or how do you recognize that?

I see persistently too little clarity about the construction of wall and lintel here, but only the lintel in the facing shell. That is clearly not professionally executed, because this pointed arch is too flat for the stones to "clamp" together and hold each other. That it "only" slips on one side is actually a small miracle.

11ant has explained it comprehensively and professionally. There is no need to do it again—

11ant has explained it comprehensively and professionally. There is no need to do it again-

Sorry, the explanations from 11ant are unfortunately not plausible. Technically, the cut-right curve is okay. A minimum super-elevation of 2cm is - unless I am squinting - maintained. The radius of twice the length also fits. There is nothing to criticize technically.

It is merely a masonry lintel for the formwork. Statistically, it has no significance for the actual masonry or the window.

That’s exactly what we don’t know, whether and what connections exist between the structural and facing masonry shell here.

Whereas these are not facing bricks but solid clinker bricks.

Not "but" but "and".

Sorry, the explanations from 11ant are unfortunately not plausible. Technically, the segmented arch is fine. 2cm minimum camber is – unless I’m squinting – met. The radius of twice the length is also right. There is technically nothing to criticize.

If the standard (tolerance) here is more generous than common engineering sense, then it’s clear what I prefer. I don’t need much imagination to claim a causality between the damage pattern and the questionable execution.