I recently replaced the head on my 2003 Hyundai.

I recently replaced the head on my 2003 Hyundai 1.6 liter accent and I have DOHC I did align the marks on the camshaft sprockets with the camshaft chain, but I noticed when I manually turn the camshaft over 360 the marks on the sprockets aren't aligned with the marks on the chains shouldn't the line back up? Being that I already aligned them?, Is this normal? This is confusing me, any advice will be appreciated