Warlock Demon Skin -spell not working correctly?

Demon Skin should be giving 40 armor + 3 health every 5 sec. Armor buff works fine but it seems like the health regeneration is not working correctly. In combat I counted that I get +3 health every ~2 seconds, though it should be 5. I have no other buffs on that could be giving the increased regeneration. This makes pulling a big pack of mobs pretty much faceroll on lock (even though you rarely get the chance in the crowded tirisfal
)
I tried fighting without demon skin -> no regeneration in combat. Again with demon skin on the regeneration rate was crazy, so the problem is in the spell. Again, there might be something I don't know and maybe its working correctly, just seems really strange.
Have any other warlocks noticed this?

I tried fighting without demon skin -> no regeneration in combat. Again with demon skin on the regeneration rate was crazy, so the problem is in the spell. Again, there might be something I don't know and maybe its working correctly, just seems really strange.
Have any other warlocks noticed this?