Skeletal Arsonists Cannot Blow Up SRS

Title self explanatory, no matter how low they seem to get they are not valid targets for the arsonists detonation. They are marked to indicate they CAN be blown up but no matter what happens or how low they seem to get they won't be. It still targets skeletons just fine.

Im having the same issue.. cant find a workaround

SRS are low health and glowing red but cant detonate them