Elemental sundering - Anyone able to make it work? Seems off from time to time

Trying an elemental(ailments focus) build with huntress.
Using the 3 elements and was thinking elemental sundering would be a bit more punchy.
First off, i am not sure if it bugged but it seems from time to time it does not trigger, like i run around the zone, i see the initial animation but not the detonation.
Not sure if it is because it does not detonate before the the ailment stop to apply or not.
Also it seems it does not work well on "corpses", as very often it does not trigger.

For the ones building it, which support gems are you using?

The damage i have on it is not really punchy.

If the ailment times out before the detonation happens then it does no damage. Same thing with corpses. The skill does considerably more damage against frozen enemies than burning or shocked, and I mostly use it to finish off enemies frozen but not killed by Glacial Lance. I use elemental focus and magnified effect on it (since it can't inflict ailments anyway). The one that gives 12% more damage per ailment on the enemy is also a perfect fit.