ᐅ Stains on cement screed floor

Hello
My flooring installer applied a cement-based leveling compound twice. Now there are some very unsightly spots. The floor has not yet been sealed or sanded. Will sanding remove these stains, or would it be better to apply a primer first and then level it again? Thanks for your feedback

I don’t see anything unusual. Just file down any small burrs, vacuum, and apply adhesive tape. There are just cement residues, so what? That’s always the case. There will be a covering on top anyway. Or didn’t it cure properly? Karsten

I don’t see any special issues here either...

So, when it is mentioned that the floor will be sanded and sealed, I assume that the floor is intended to remain as it is, and it is not just a leveling compound or something similar.

Otherwise, it obviously looks awkward.

Hmm. Is that going to be covered? Or not?

These are typical drying marks that cannot be prevented. However, they are only superficial. Once the floor is sanded, they will disappear. Applying filler again is pointless because the same issue will occur.