How/why the hell....

[Xeram]

Is acid normally explosive? I ask because I managed to blow myself up with my own acid golem (thank god for soulguard)

Well golems kinda do that thing where they turn into a cloud of the reagent they're made of and inflict horrible horrible things on anyone nearby.

What did you expect from a golem made of acid exploding into a mist of death right in your face? I'm surprised you weren't dissolved completely from existence.