Taking “Cosmic Insight” increases the CD instead of reducing it. With just “Acuity” skilled, base cooldown is 5s. Adding in cosmic insight, it appears to go up another 2s for every point in it, but the 10% cooldown reduction on the node works as well.
Edit: Did some more testing, the 2nd point didn’t appear to add anything to the base CD. Only the first one was bugged