Grammar Time

Here's the sentence in the book I'm reading:

By doing so, you may be able to avoid having to wade through pages of
highly technical, unfamiliar material that does not really
concern you. [emphasis added]

I think it should say "that do not really concern you", because I think
the last part of the sentence should refer to the pages, plural, rather
than the material, singular. Or maybe it's just up to the author. Or,
and this is quite possible, I'm just bored.