Almost immediately after our basement slab was poured, the concrete contractor sealed it to keep red clay mud, etc. from construction from penetrating and staining the slab. Very shortly after, though, the slab started turning blotchy as shown in pic below. The builder says this is normal for concrete curing (it’s been about 2 months since it was poured) and that it will all turn light over time as the concrete ages. The other option is to reseal it when construction is done. I’m afraid we are going to have to strip the sealer first to reseal it which might prove difficult with finished walls in the basement.

First, is this normal? Second, what are my options to have a uniform looking concrete? Personally, I think it was sealed too soon and moisture got trapped (which I saw after the fact at another of this builder’s houses) and the builder is trying to pass off as “normal” as I’ve never seen this happen with any other concrete we’ve ever had poured.