Vampiric Embrace proc range
 

The proc on vampiric embrace doesn't go off and gives the message 'you are out of range get closer' when fighting larger NPCs unless you literally stand right underneath them. I have noticed this on giants and every large NPC in posky/hate/fear such as Essence harvesters, Ashenbone Drakes, etc.

I'm not sure if this is occurring with other types of procs, but I believe the proc range should be the same as melee range.