It should not work as a detonator on any armor, but I will have to test that out.
Are you using the Shield Bypass evolution at rank 6? I wonder if that is glitching it.
Yes it is evolved as followed:
rank 4 detonate
rank 5 damage over time
rank 6 shield penetration
It is so weird, i seem to detonate on atlas if I use it on the sides or behind the atlas, but not in front. I can detonate any other enemies like praetorian/scions, banshee/brutes, pyro, prime, dragoon, turrets, etc.
If you have any luck looking into the dlc pack for omega and if have any luck looking into the code, it seems armor detonation was intended, its in the script. I believe they didn't do that on mp because it might be OP? Either way if it was intended it would be nice if it was consistent on detonating atlases. It can't be glitching due to my modding can it? I only changed the damage of flare to undefined because I felt it deserved to destroy nothingness, that's the only "mod" I did. Also the game is fully patched so all the mp change (accept for singularity) came to sp.