I got flamed on another thread for saying this, too (sigh).
Below short list* (off top of my head, I'm going to bed) of words that do not appear on the phonics test because they don't follow the phonics rules the kids are expected to follow. A child who can read would say them wrong & fail these on the test although the words were pronounced correctly in conventional English. When DS reads them he has to disregard the phonics rules he's expected to follow for the test. Not that in learning to read DS is only being taught the narrow test phonics, but an emphasis on him learning the phonics rules could be at the expense of teaching him the rules for saying other words correctly. And therefore interferes with word recognition & that interferes with fluid reading.
Ready?
dove, goes, to, you, one, great, find-kind-mind, does, bread-ready, some, do, love, live (as a verb), one-done, gone, two, eight.