Bug with CWC

I have CWC setup that doesnt work and Im fairly sure it is a bug.
I have a 4-link with Scorching ray(imbued with lvl 1 lifetap)-CWC-purifying flames-combustion.
Purifying flames is not proccing.
I have the blood magic keystone.
My guess is that the game thinks I do not have enough mana to cast the purifying flames but it shouldnt be so, since I have blood magic.