The teaching that God does not know the future is interestingly developed in Whitehead's thought. See especially Process and Reality which I read and failed to understand some 30 years ago. It seems to me that what Peter says about God's relation to time suggests that what we call the future is part of God's "now".
If I were going to work on this I'd re-read Whitehead first. My money is one its being non-Biblical and heretical. However, thinking that God beholds past present and future, so to speak, all at once, has its difficulties.
But then I never expected to understand God, and enjoying Him, not doping Him out, is what I hope for.
Name them.