poured concrete basement wall is layered

[Mike Ad]

Dear friends:

I am house hunting, and fell in love with this newly built 2-story single family house, with unfinished basement.

The basement wall is a concern (see attached picture). It's poured concrete, however looks like a three-layer cake. And the top layer has a darker color. Not surprisingly, the builder doesn't have any convincing explanations.

Can anyone advise what happened? Is this a serious issue?

Should I consider this house and pay for a home inspection at all?

BTW, the wall seems dry (there is a dehumidifier in the basement), and the dark layer doesn't seem to be caused by water damage, instead, it seems like a different type of concrete was used. I am from New Jersey.

Thanks a bunch!
Mike