some ppl need to take out of his head the "LD is a 20s invul" idea, it's not, first of all if we somehow manage to squeeze all the efective duration it will be 18s at best, if living dead reach 10s the buff disapear and get wasted, if walking dead reach 10s you die and your party contribution it's wasted, for no mention you have to know the extact moment on each fight and have no delay whatsoever to fit the last second of living dead with the TB and get the proc wich it's imposible unless you are using 3º part programs or something similar.

Now the walking dead efective duration can only be archive by WHM, it's imposible for AST and SCH to max your hp in less than 1 second and most if not all healers preffer to get rid of the buff as soon as posible except unless you get any real good benefic from extend it as much as posible like several TB at once but those cases are extremly rare and not worthy the effort most of the time. LD it's just incredible taxin for AST and SCH and need to be fixed.