Warping wooden staircase and cracks in the wood

Hello everyone!

We moved into our new building in November last year after a relatively short construction period of 7 months. We had a concrete staircase installed with wooden tread steps, as well as wooden cladding on the railing. It is parquet-glued beech wood with a lacquer finish.

Now, after not even 8 months, both the tread steps and the railing are massively cupping, the outer sides of the wood are pulling upwards, so even the silicone joints have already cracked and in some places the glue in the middle of the wooden boards is coming apart. The difference from the edge to the middle is now more than 6mm.

The humidity in the house is actually not high due to regular ventilation and consistent heating despite the fast construction period. Right next to the staircase is the moisture sensor, which hardly ever shows more than 60%. Room temperature is always even due to underfloor heating. We had a dry phase in April/May with humidity of 30% over weeks. Is this due to too rapid drying from ventilation and the wood surface shrinking? Has anyone had similar experiences?

At first, I didn’t think much of the cracking silicone joints because wood does expand and contract. However, now we have noticed the cracks in the wood in the middle and you can see how it is lifting at the edges.

I am very grateful for any input!
Regards
CW

Do you perhaps also have pictures for that?

At first, I didn't think much about the tearing of the silicone joints because wood does expand and contract. However, we have now noticed cracks in the wood in the middle, and by now you can see how it is lifting at the edge.

However, we have now noticed the cracks in the wood in the middle

That's not a crack?!? That looks like a scratch!

Unfortunately not. At the gluing on the top and right, it is also coming loose and lifting up in a triangular shape, standing above the rest of the board - it is not clearly visible in the picture.