I had recently been hunting Resuscitants and had been fortunate enough to have PFE cast on me. I combined that with our damage ward and noticed that when hit, both would trigger and reduce the damage, BUT our damage ward would never get put back up after its usual cooldown from triggering. PFE stayed up the entire time, the damage ward was up, but the damage ward never triggered again, while PFE kept triggering while the spell was up whenever I was hit, so it appears that PFE interferes with our damage ward ability from resetting even though it will trigger when its first put up.