Warlock Improved Drain Soul not proccing correctly

[Elumny 0]

I noticed Improved Drain soul not proccing that often when specced at 1/2 which is a 50% chance to proc, but once I put 2/2 points into the talent for a 100% proc chance it is not proccing every time a mob dies while being drained with drain soul.  This is was tested on Nighthaven PvP.

[Zancon 117]

Exit the game and clear your WDB by navigating to your install directory and deleting the WDB folder.

Then re-launch the game.

[Barisarta 0]

your warlock and not the demon  needs the killing blow to proc it.