Done Runic Bombs not destroying runic golems shields

Forgive me if I'm just doing this wrong, but I've watched YT vids, Googled, etc. In Mysterium, the runic bombs don't seem to be destroying the runic golems shields - which is the only way to inflict damage and beat them. I know I'm directly hitting them with the bombs - at least part of the time. Is this a bug or am I overlooking something embarrassingly obvious? Thanks!

 

Prehaps because its triggering an explosion that is blocked by protections? CAN confirm works in sp.

 

The golem is in Mysterium. I tried it in single player in Mysterium and the Overworld and can't get it to work. Maybe I'm doing something wrong. Do you have any tips on where to aim, Tyler? I SWEAR I'm hitting them. I'm practically on top of them and taking damage myself. lol

 

works in single player i usually drop them on there head. if they flash red then it should have broken the sheald