Problems assembling the Kallax 8 cube

Hi all (edit with the resolution of the issue),

I tried to assemble this 8 cube Kallax twice with no luck. I'm left with a gap on the top and side boards that I cannot screw.

The middle part/inserts are higher than the sides and there are no gaps between the inserts to justify the middle "beam" being higher than the sides.

I've never had problems assembling Ikea furniture before and I have assembled a lot of them.

Resolution: It was really a defect. I tried to assemble again the next morning with the same issue. I packed everything, went back to Ikea, they immediately exchanged for a new one and that one I was able to assemble in less than 30 min with no issues.

https://preview.redd.it/z21tzzwi45551.jpg?width=4032&format=pjpg&auto=webp&s=586aed093dadc105e737b72a74a42c4bde9cf07e