Hex Blast, Blasphemy, and Support Gems (Plus Incorrect Skill Video)

Currently trying to make a build utilizing blasphemy and hex blast but running into issues and noticing inconsistencies with the way curse supports work with casted curses and blasphemy.

* self casted curse + impending doom + hex blast cast = doom blast ✔
* blasphemy curse + impending doom + hex blast cast = no doom blast ✖

* self casted curse + cursed ground + impending doom + hex blast = doom blast ✔
* self casted curse + cursed ground + impending doom + monster walks out of cursed ground = doom blast ✔
* blasphemy curse + impending doom + monster walks out of curse range = no doom blast ✖

* self casted curse + decaying hex = decay ✔
* self casted curse + cursed ground + decaying hex = decay ✔
* blasphemy curse + decaying hex = no decay ✖

Also, I understand that in the recent patch notes it was explained that Hex Blast's wording was updated to indicate that it only detonated one curse on an enemy but the skill video for hex blast shows an example of, and states that "If a monster has multiple curses, all of them will be detonated". Aside from my disappointment that this was implemented and removed, the video should probably be changed to reflect the updated effect of hex blast only detonating one curse on an enemy.