Elemental invocation never triggers socketed spell (sniper's mark)

elemental invocation meter at top left of game screen eventually goes to 100% with my shocks and freeze, I'm playing huntress

but never actually trigger socketed spell, which is sniper's mark. It's 0.5s cast time, which means it should need 50 energy. elemental invocation has max energy of 500. Why is it not triggering spell at 10%? I clear whole endgame map and it's stuck at 100%, going to town and it resets to 0%. Sniper's mark is never triggered and cast.

Elemental Invocation has to be casted manually (be assigned to the skill bar) unlike other trigger gems so it won't help with auto casting