First the typo, in sabertooth its a gAuging claws node instead of gOuging claws.
The spriggan form bugs. Now part of it might be bugs, part of it intentional so i will just list it all.
It is mainly totem related, the half of mana cost is paid in life does not work if you picked up the thorn totem node. It forces you to pay half of the mana cost in life, but it still takes the full mana cost for the cast.
Also healing totems stop healing if that node was picked up, even when the skill description states that they now ALSO attack which implies both functionalities.