to reproduce use the storm totem and note how with no skill investment it begins attacking immedaitely.
now put skill points into the “blizzard” skill node. you will now notice a significant delay (around 1.5 seconds) before the storm totem starts to deal any damage.
this is not noted anywhere in the description for the skill node. so i assume this must be unintentional and therefore a bug.
while not a significantly detrimental bug, the storm totem only lasts 8 seconds. so 1.5 of those 8 seconds (almost 25% of its duration) are wasted.