Did you actually try to book the flight by following the links on both Google and Kayak? Google is showing the flight at $1809 now and it's possible that their cache was not updated.
Also, it's possible that flight is under KLM/AF instead of Delta on Kayak since Delta/KLM/AF are partners. And I see same flight listed under KLM for $1781.
Delta flight on Google is $1293, $1840 on Kayak