Fixed glazing plastic window is leaking

Repairable: Yes, no problem, it's actually a small matter.

It was glazed on the construction site, since it is fixed glazing, only the block bridges and the plastic glass supports are incorrectly mounted/placed.
I don't have it on my radar, how old are the windows??

The windows were installed in late summer 2018.
Unfortunately, I was not present during the actual installation.

Here are pictures from the whole view.

Better photos already. Please try again, then it will definitely work to get the window as a whole, that is "everything," in the picture. It would really be important. Questions: Is the window on the upper floor? Or in the attic? Is this a new building from 20218? Is there a ventilation system? Question: Can you open a sash and photograph the horizontal transom/post in the rebate so that we can see drainage, seals, and corner connections = do not get too close when taking the photo.

The window is on the upper floor, which is also the attic. Although there is a high knee wall of about 1.60m, there is still a sloping roof. The house is from 2018. A ventilation system with heat recovery is present; in front of the window, an outlet can be seen.

Already better photos. Please try again, then it will definitely work to capture the whole window, that is, "everything". It would really be important.

By now, even the most inexperienced readers should have understood what worlds lie between an illustration without and with contextualization when it comes to portraying the helpers :)

What is your tip now, what could be the reason? What I wonder is: everything that was covered by the tape remained dry in the end. So can I fix it by sealing the joint between the frame and the mounting strip, e.g. with mounting adhesive?

I will summarize the essentials: #1 B.Baumeister OP: …solid house built in 2018/2019…plastic windows…floor-to-ceiling fixed glazing about 2m (width) and above that 2x1m casement windows….fixed glazing leaking… “plastic seam” … moisture ... slightly brownish… (1 photo close-up, edge of glazing bead wet) #2 i_b_n_a_n: … clear warranty case (IMO)… #4 Tolentino: … contact the GEU/GÜ or window manufacturer, depending on who your contract partner was. #12 B.Baumeister OP: …(4 photos) #13 B.Baumeister OP: … humidity… 29% #19 B.Baumeister OP: … (7 photos) #25 B.Baumeister OP: … window… installed late summer 2018… (2 photos) #27 B.Baumeister, OP: … window is on the upper floor which is also the attic…. house from 2018. Ventilation system with heat recovery…in front of the window you see the outlet. (4 photos) Since you (B. Baumeister) are presumably an absolute layman in the field of windows, I would urgently recommend consulting a construction lawyer and/or an expert for windows. Based on the photos, I suspect there could be defects that might in the worst case even pose a danger to life and limb.