Summon Raging Spirits canot be detonated with Explosive Demise

Summon Raging Spirit cannot be detonated with the Skeletal Arsonist's Explosive Demise skill even when under the intended health threshold or even using the Support Gem Sacrificial Lamb (the graphical effect on the minion when it can be detonated is displayed correctly)

I have the same issue. Max hp under the threshold and the red circles appear on the skulls, but they cannot be detonated.