Not sure about it, but it seems that Heat the Soul has a cooldown when used with the Spear's primal burst Wild Throw (the internal cooldown of Heat the Soul was removed in November 28, 2023).
If you use Wild Throw, then reset it with Blood Reckoning and use Wild Throw again, the second application doesn't triggers Heat the Soul (it works fine with every other weapon).
Can someone double check it please?