Very messy parquet laying work - Is rework not possible?

And you're only now coming out with this picture? Now I feel fooled. What have we been discussing at length here - about the edge of the baseboard? Of course, this is complete nonsense and as a DIYer, it was the first time I laid parquet myself in my own house. Even my first own attempt didn't look like that. This is total botching!

The first photos were probably of lower quality and the crooked joints couldn't be seen, which I am of course sorry about.

Another round of stress with this parquet layer. Now the staircase is affected. Yesterday it suddenly looked like this. According to our builder's assessment, the stains were caused by the adhesive. The parquet layer admits this but claims that after his work the stair risers had to be painted. "After all, these are only 'pre-coated' stair risers, so the painter only needs to paint once and does not have to prime anymore." The builder and our building inspector were very surprised by this statement because such stair risers are basically finished, coated components in different decors that are not to be painted. It is still a new building and not a newly renovated house. The parquet layer refuses to make corrections; this would already be the second.

The man apparently also likes distinctive acrylic joints.

Stains cannot be seen on the pictures. But the grout lines stand out.

OK, I have seen it now. You mean the risers? They probably need to be painted again. In my opinion, that is a defect.

Have you tried drying the stains with a hairdryer? Maybe they are just moisture stains?

If the stair builder delivers and installs the risers, he is also responsible for the proper completion. Even if the final coat of paint is necessary.

If the staircase builder supplies and installs the risers, he is also responsible for the proper completion. Even if necessary, for the final coat of paint.

Even if another trade goes over it afterwards. I find that questionable.
At least as questionable as the fact that the riser and tread are supplied by different trades. Warranty and scope-of-performance disputes are practically guaranteed there.

So, our developer has nothing to do with the covering of the stair steps. It was agreed that he would hand over the staircase to us in its raw state. Several measurements were taken before the house was handed over. The parquet layer completed the stair steps entirely: the last layer of concrete, the adhesive, the white components, and the wooden cladding of the steps. The staircase and the entire order were finished in January. In my opinion, the stains were caused by the heat last month. The white nosings are probably of inferior quality and the adhesive is seeping through. The parquet layer claims that the white nosings absolutely must be painted over by the painter. What is the point of these white components if you have to paint over them? Our construction manager and the building surveyor are speechless. They have never seen anything like this in a new build. As standard, such white components are installed as finished parts without being painted over. Do you also paint the back wall of a cupboard or any part of it? They recommend that we consult a lawyer. The parquet layer does not respond to my email. I have set another deadline for rectification.