That's weird. Cause in my adept run I only ever got both effects once, and that was the single wave where by chance the two pentagrams overlapped. Every other wave, when I stepped into one pentagram I didn't get -CD. But when I stepped in the other, I did. Same when I had the Cheater item and two Pentagrams. I didn't get +40%, I got +20% so only the effect of one.