New parquet has small holes - parquet beetles? Parquet in new building

... With full gluing, the most likely scenario is that the beetles or the holes were eaten _before_ the gluing, as it is unlikely that they move (can move) in the adhesive. I would remove a board and check whether the holes go all the way through. Also document whether there is wood flour or not. "Through" and "flourless" are indications that it was already there before.

What I find confusing, however, is the beetle find with you, but that might also be just a coincidence.

Good luck!

Flourless is difficult to assess... many holes are flourless, but there are also some that are not entirely "empty." The problem is just that everything is full of flour anyway from laying etc... flour could also have flowed in afterward.
Removing the board would have to be done by the floor layer.... but we have also said that we want it in writing that there is no infestation. Also for possible future damages.

As I said, the beetle we found is very certainly not a parquet beetle, but a Cossonus... the pictures of Cossonus in Google image search almost perfectly match the beetle we photographed (see my first post).

I mean, flour under the boards. Flour always sifts down. It would only be to exclude.

If the floorboards, as you already said, were left "open" at the installer’s for several weeks, the most obvious assumption is that the holes appeared during that time.

I would also almost exclude the manufacturer (heat-treated).

how and where exactly they were stored I do not know. however, I think that the manufacturer’s packaging/sealing has not been altered/opened.

Or a few boards slipped through the manufacturer's internal quality control: then holes inside, but larvae dead.

I think, however, that the manufacturer-side packaging/sealing has not been altered/opened.

Probably not intentionally, but the infestation rate would fit with how "often" packages sometimes have holes, right?